Your Zero Is Off And You Don't Even Know It

______________________________________________
GEAR I LIKE
Hearing Protection: goaxil.com/pages/gs-extreme-a...
My favorite scopes (blog post) backfire.tv/scope
My favorite rifles (blog post) backfire.tv/best-hunting-rifle/
Above links, or the pages referenced, contain affiliate links. Commissions earned.
______________________________________________
The Backfire KZbin Channel is owned and operated by Backfire LLC, a Utah limited liability company.

[@mattcormier983]

For hunting, cold bore zero is what matters. Shoot one shot every day and record its position. Compile about 10 and use that as your zero. Light profile barrels shift a lot and with very few shots in my experience.

[@timothym2241]

I agree. It’s also valuable to know, whether your cold bore shot is different than the rest. Assume it is, unless you know otherwise.

[@GreenFields-7777]

I have a carbon barrel and I would never buy one again. It’s hard to get any kind of really good accuracy grouping unless you’re prepared to sit there all day. And forget about taking a shooting course because the amount of shots you need to take as specified time is infeasible with that type of barrel.

[@HazardousRob]

Really? I've had 3 and they're all flawless

[@anthonyhilton4168]

I’ve got a Savage ultralight with a carbon fiber barrel and it’s shooting 1/2” or better (on a 3 shot group). I also have an Eric Cortina tuner brake on it, maybe that’s the difference?

[@McgSpook]

I dont shoot hunting rifles much so Im assuming it may be more of an issue with the thinner barrels and such. On good heave match barrels I dont see cold bore shift. There is clean bore shift of course. Personally, after a good cleaning I will shoot 10 rounds or so to foul it up and leave it alone until accuracy starts to degrade. Rinse, repeat.. There was a time when i thought cold bore shift was happening and what i found out (for me) was that it was actually cold shooter. To test this i took another rifle with me each day and did my first 20 or so shots from that other rifle. Then i shot the rifle i had a recorded cold bore on. Amazingly enough, no shift. That made me realize i needed a lot more work on my body position mechanics. Others may have different experiences.

[@ottokittel709]

thirty years ago I had purchased a rem model seven, it shot 1 in groups when new, sent it off to have the barrel action refinished with dull finish, was very shinny bluing. the gunsmith refinished the rings and mount also. put rifle back together and it still shot good for about 2 years deer hunting, less than ten shots total and four deer in the freezer, then every thing went to crap, 3-4 inch groups. glass bed the stock, no changed, it sat in the gun safe for twenty five years. recently I pulled the old classic rifle out of the safe and did a completed relook, come to find that a tally base was loose, I knew right away that was the culprit. lock tight the bases on and the rifle now shoots just under 1 inch groups. life is good again !

[@johnnyadams1755]

Right away...25 years later😂

[@jayblemsin4226]

Whats a tally base ?

[@SammyMoore-tg5gs]

@@jayblemsin4226 Talley is a company that makes quality scope rings and bases. Highly recommend.

[@JDsModernMartialArts]

​@@jayblemsin4226Talley makes scope rings and mounts. 😊

[@chasetheoutdoors]

I couldn’t imagine shooting my rifle less than ten times in over a two year span.

[@patrioticguy1791]

I shoot PRS and when I have a zeroed rifle in Indiana and go to Northern Michigan or Southern Indiana or even 2 hours west in Illinois the following day, I have to re-zero because sometimes it's still off even if your equipment is not loose. Temperature, barometric pressure, density altitude, all kinds of stuff can affect your zero from one day to the next.

[@onebadjack1313]

Have you tried the 4dof zero range function? I've been meaning to see if that works. I didn't realize what it was til recently.

[@cijetovina]

​@@onebadjack1313 I think they call it zero angle

[@JourdanUrbach]

What scope are you running?

[@onebadjack1313]

@cijetovina You are correct! I had to look at my 4dof. Apparently, my memory sucks.

[@hallovelo2478]

@patrioticguy1791 A rifle is never zeroed. Also the change of light will affect your pint of impact. For sure it depends on what your goals are on hitting a target.

[@andreasgauckler3152]

One point not mentioned is if you wear glasses. This can impact your parallaxes without realizing. I never realized cold bore issues with my Model 70 or my Blazer. This usually is a thing with extremely thin barrels e.g. Kimber from my experience or can be caused by a barrel with improper stress relief due to incorrect heat treatment which should very very rare. I like the turret stickers.

[@briansteele1378]

I totally agree with you in that everyone wants to focus on group size, but none of that matters especially in a hunting rifle if it can't consistently hold zero.

[@MrMagoo321]

Its common knowledge that pencil barrels are less accurate and shift after heating up. Heavy barrels are more accurate and have little to no shift after heating up. Three shot group adjust the scope then check and adjust another Day. Patience is a virtue

[@jimyeats]

All things being equal, sure, a pencil barrel will have a higher chance of being less accurate (or precise) than a heavy barrel, but not inherently so. Same with heat, a pencil barrel will have a larger chance of heat opening up the group, but a high quality barrel that is properly stress relieved shouldn’t have a POI shift. So yeah, in common practice you’re correct, but a lot has to do with barrel quality.

[@MrMagoo321]

@@jimyeats this company says their Sporter barrels are expected to produce 1.5" three shot groups at 100 yds. I'm getting 1" cold bore and about 2.5" warm. So as a cold bore it is good enough for me but since it opens up so much when it heats up then it's no good for target only hunting. Makes sense!

[@Leonarco333]

Traditional pencil barrels are absolutely notorious for shifting zero. I have a stress relieved pencil barrel from criterion that doesn’t. When it gets warm, the group sizes open, but the center doesn’t move. It doesn’t take very many rounds for that to happen either.

[@syednoori3799]

this was the exact problem i had ,missed an ibex about 9,10inches down, at 350 meters, i rechecked everything at last it was the suppressor that was lil bit loose, i thought i cant be the problem so went to the range to check , you know what happened,

[@matthewpenn407]

Man... thank you. It so easy to forget to tighten everything down. Had my rifle out to the range two weeks ago and it was perfect, went out yesterday and couldn't hit a thing. Just now checked it after watching this, my rear scope mount was loose, bipod was loose, and my suppressor was backed off about 1/8th of a turn!

[@jasonshults368]

I'd hate to see the condition of your car/truck. And the rest of us hage to share the road with you.

[@matthewpenn407]

@@jasonshults368 My tahoe is immaculate. The problem is that I have to drive highway 4 to and from work. Look it up, it's in south Texas. One of the worst highways in the Untied States.

[@danroseveare3090]

Everything starts with the shooter. If your shooting form is consistent then you go looking at equipment and other potential issues. We all must pay attention to pressure, humidity, wind, lighting, thermals, etc. At the end of the day the best rule to follow is that if you're not sure of where your shot impact will be, don't take the shot. There's nothing wrong with an ALL STOP if things are wrong. In fact, that's the safest thing to do. Great video. Thanks for all the work you and the crew (family and friends) have done to provide these videos and information for us so we can all learn.

[@brutushusse]

Ambient temperature and powder temp tend to cause a shift in both velocity and point of impact.

[@mikevieira6373]

What about scope cant ?….I shoot out at a buddies property, but the ground isn’t always level where we shoot. I’m running Holland levels on all my scoped long guns now. You hit the light conditions point very well. I used to get frustrated sighting in, I’d shoot on a weekend, & get the gun dialled in during mid day. Then I sometimes ran out to the shooting range after work when the sun was going down, and my point of impact would change, not a lot, but enough to frustrate me. I soon started sighting in later in the evenings when the sun wasn’t hitting my scope at different angles and noticed my point of impact was never far off week to week.

[@MrJAvB]

Jim, great video. One thing that I would love to see addressed is the condition of the bore during the cold bore shot. I would love to see your advice on storing a gun (clean barrel, dirty barrel, or an oiled barrel and pushing a few clean patches through.. etc). This might be an explanation to why the shots after the first shot seem to be more consistent (oil is gone and barrel is fouled). Competition shooters could just foul the barrel with a few shots before competing, but for hunters this often is not an option and certainly it isn't ideal. Would be an interesting topic to address, and maybe combine it with a barrel cleaning video (should you clean a bore to bare metal, should you keep it consistently 'fouled-clean' or maybe shoot x amount of shots and then clean and foul the barrel and never touch the barrel until accuracy drops off again). Lots of things to think about :)

[@jason200912]

Mostly clean but don't clean it so hard with ammonia that it reveals eliminates the copper filling up those pores

[@Eburns77]

That’s also what I’ve heard with regard to not cleaning out the copper fouling. What I’ve heard reported is the muzzle velocities will actually go up a little bit with the initial deposition of copper. Worth noting on Jim’s last point with shooter position is the angle of the gun with respect to vertical, which if not eliminated will throw your shots around a bit.

[@pickardjw]

Easy solution: don't clean your barrel...ever

[@randallreiners3703]

Plus shooter error !

[@chrisgunsandguitars1403]

My thoughts are if a hunting rifle only, clean the bore every 20-40 shots. This could take a few seasons; so a patch of light RemOil down the bore after hunting and put her away. Remove the stock if it got wet and address that issue. Rifle should be gone over just like you would a vehicle before a long trip. Check that everything is tight. Then hit the range and check zero. Then don’t clean it until again 20-40 shots. Many rifles can be a little different. Most rifles shoot a little better once a bit fouled. However, your rifle will be cold when you shoot at your deer/elk, so knowing how your rifle shoots cold and fouled is a good thing.

[@smoakngun]

Very good information. I really enjoy your videos and your honest, unbiased opinion on equipment. I agree with you about the "Cold Bore Shift" phenomenon.

[@CutlassOutdoors]

Incredible. Very well done video that covers a lot of common reasons for losing zero. I learned something new. Thanks!

[@jmlorenz]

I learned a lot from this informative video, thanks Jim. My comments are in regard to the effect of barrel temperature on the POI: 1. there was no discussion of the effect of barrel temperature on barrel harmonics; 2. there can a very broad range of variation in barrel temperature - which will vary with the barrel material, mass, and surface area - e.g. from ambient temperature, which could be 30 degrees F to > 106 degrees F after 8 shots in my rifle; 3. Eagleye Hunting Gear showed quite a bit of difference among rifles in the change in POI with increasing barrel temperature in a KZbin video; 4. It is important to distinguishing between the effect of increasing barrel temperature and fouling with repeated shots. Of course when you're hunting the most important shot is going to be with a cold bore.

[@user60521123]

The second point is really fascinating. It’s call the Law of Large numbers in stats. You’ll know when you’ve shot enough rounds to zero when the center of the groups no longer moves a significant distance. Great video!

[@phild9813]

I have zero interest in knowing the answer to this question for a big game hunting rifle. The first shot is by far the most important, and maybe up to two after that matters much less. Some rifles wander a lot after getting hot, some don’t.

[@blantant]

​@@phild9813this assumes the human doesn't overestimate their skill and has a rock solid platform.

[@user60521123]

@@phild9813 Basing your accuracy on one shot will not tell you anything about the accuracy of your first shot. If you need your first shot to be on the money, you should base it on an even larger group. You can do this while allowing your rifle to cool off. It’s about probability not luck.

[@johnkissam8312]

Really appreciate your contribution. Smacked my forehead and…..of course. Also remembered that data should not be anally extracted !! Otherwise it’s simply so much B.S.

[@PoliticallyInsensitive]

5:32; there's a huge difference between "not tiny little groups", and having a target that looks like you were using a shotgun

[@ghostfame5719]

Hahaha lost it when you started hammering that scope

[@clintonlayne9253]

My thoughts were I wonder if Leopold warranty will cover it. 😂

[@beenstork]

2:00 Last time at the range, I had this exact thing happen. I was shooting a new barrel and getting decent groups. Then I started noticing my point of impact shift. At first I thought it was just the barrel settling in. Then I was letting the barrel and suppressor cool down between shot strings. I reached up to feel how hot the suppressor was and noticed a tiny bit of play. I re tightened it (maybe a 1/10 of a turn) and then magically my original POI came back to the original spot. I learn this lesson first hand that day. Now I check the suppressor for snugness often

[@MrMagoo321]

@backfire Jim, Great channel!! Great advice!!! My gun strings hard after the third shot so that's where's its zeroed. Its a pencil barrel so you have to wait what seems like all day for it to cool all the way. Ive been going through this gun as it had issues which you stated in this video which were affecting the zero along with my shooting it hot. I'll double check three cold shots next time i shoot it as its a hunting rifle and i doubt i will get more than two or even three shots at anything.

[@bryanduchane2371]

Also. Lifting your head off the rifle and changing your cheek weld will cause accuracy issues. If your action and magazines are working properly, there is no reason to lift your head. Watch competitive shooters, they only lift their head when changing targets and distances.

[@RealSB]

Every time he shot it was the first shot...

[@Gunrunner223]

Absolutely. Especially if your scope is a fix parallax scope, and your shooting a distance that's different from the factory setting. Most deer rifle fix parallax scopes are set at 100yds. But some shotgun, muzzleloader, or rim fire scopes may be 50, 60, 75 yards set. They all work ok for most deer hunting ranges in the southeast, but my paper punching, or coyote guns, all get adjustable parallax scopes.

[@RealSB]

@@Gunrunner223 I've had friends that could put their face and eye in the same exact place every time, I'm not that guy.

[@Gunrunner223]

@@RealSB me neither

[@VK6AB-]

Some really great points in this presentation - some thoughts, the instructors comments on Sun position are real but are a much smaller issue with very good glass and coatings and point of aim being through the centre x hair, (centre glass) but can be well off with on cheaper glass, with fewer coatings and when using large holds well away from the centre of the glass. In my view there is little point to a Christmas tree style reticle with poor glass and coatings (as the error will increase away from the centre of the glass). Good glass, good coatings (and plenty of them) plus relatively simple reticle e.g. 1/2 mil dot is the way to go (in my view).

[@josehorta4581]

Thank you for sharing all your wisdom I as a new hunter I like to learn from people like you who have experience and you explain well thank you I didn’t know there was a difference being a little lost that’s why it didn’t hit them

[@jimyeats]

I think cold bore “shifts” come predominantly from people cleaning their barrel between range sessions or between zero’ing their gun. You scrub that barrel and you will absolutely have POI change for a shot or so. You commonly hear cold bore shift discussions with fairly inexperienced shooters or casual shooters. I don’t ever hear precision shooters have issues with cold bore POI problems.

[@Iceaxehikes]

I free floated the barrel of my Ruger m77 and bedded the action in the stock because it was shooting wild. Tried all kinds of different torque on the stock screws to no avail. Finally realized it was just a piece of wood and sanded the forend away from the barrel and bedded the action. It really helped the rifle a lot. The variability from shooting from a bipod vs resting on a bag is much less than it was. Will find out next month if i drew an elk tag this year or not. Deer tag for sure.

[@Gunrunner223]

Ive done the same with my 1995 model, Ruger m77 mark II 270. Even with handloads, about 2" inch was as good as it would do. Bedded the stock, floated the barrel, lightened the trigger to 2.2 lbs, played with different torques on the stock screws, and only got it down to 1.25" inch. My theory is, before the Ruger American, savage axis type budget rifles, that shoot deadly accurate, most rifle manufacturers didn't put a lot into accuracy. And rightfully so. Us hunters didn't either. I knew a lot of guys that 3 shots hitting a pie plate at 100, was good to go! Now that budget guns shoot 1/2 moa out the box, those higher end guns have to shoot well also. I've got a new savage 110 timberline in 243win, that with handloads shoots 3/8" all day. And a Heinz 57 AR-15 with a larue tactical 20" barrel in 223 whylde, that shoots better than any bolt gun I've ever even seen shot ! Cold bore will be 3/8" from the next 5, that are all in one hole. Like a 0.2 group. Times are good for accurate rifles.

[@brandonbelchersr9496]

@@Gunrunner223Have a question if ya don’t mind, So I’m wanting to put a 223 wylde barrel on mine as well, just curious, Did you keep same bolt carrier? Or did you match the barrel with a new bolt? and did you change out your buffer spring, and use a certain weight? Thanks for any info.

[@Gunrunner223]

@@brandonbelchersr9496 you don't have to change anything. A 223 Wylde, 5.56, or 223 rem, are the same bolt face. I swapped alot of stuff, but to function, the barrel is all you have to change. I highly recommend larue tactical barrels. They have amazing reviews. And I've never seen accuracy like I'm getting. Even bulk brass fmj shoots 1.5 inch groups. Quality factory ammo, shoots 3/4 or better. Every handloads I've tried, from 50gr vmax, 52 eldm, 55 vmax, 55 blitz king, 62 sierra HP, 69 sierra match king, have all shot under 1/2" inch, and most shot 3/8" or better. Never seen anything like it. I did swap my trigger out to a timney $99 single stage 3 lb . My barrel is floated. Hope you find one you like.

[@brandonbelchersr9496]

@@Gunrunner223 thanks a lot, very well rundown. At least I know now I’m good on everything but my barrel, which will be a larue barrel.👌🏼 Thanks again and have good one..

[@Gunrunner223]

@@brandonbelchersr9496 absolutely.

[@jesseiancassidy]

The cold bore subject is really a cool one to dive into to. One thing was missed that I have run into. Action screws miss torqued make a huge difference.

[@rossholmes178]

Greetings from Australia...thanks for your work on these vids, always helpful.

[@joshmorales903]

Great content as always. I do have a comment on the cold bore discussion. My favorite hunting rifle shoots the cold bore shot 3/4in high and 1/4in right every time. I have shot 1/2moa 5 shot groups by cooling the rifle in-between shots with a barrel fan. Once the rifle is warmed up the group stays tight until round 15ish and then things open up again. I always sight my hunting rifle to "cold bore" zero...... I think it comes back to every rifle having its own little nuances and the only way to be prepared is to put rounds down range. Practice makes perfect!

[@stanleymerritt2893]

Great video Jim. Excellent information, even for experienced shooters.

[@user-mt5zh2pz7q]

Cold bore shots are all that matters in a hunting rifle. Firing 3-20 shots in quick succession won't give you the data you're looking for. It's the 1st shot, at most two, that are going to matter for testing/zering purposes. You should be waiting about 30 minutes between shots or get a bore fan to speed up the cool down process. Keep the gun in the shade and shoot in as close to the average temperature as you will likely be hunting in...don't zero your gun in an 85 degree AZ spring day if you'll be hunting in 25 degree Montana fall days.

[@benjaminwilley3578]

Enjoying the content of your videos from over the pond in the Uk.👍

[@brendavanorden9550]

Your brave. Baffle strikes occur when your suppressor is loose.

[@newscoulomb3705]

That must be why California makes it a felony to possess a hearing protection device. They're really looking out for us!

[@HookLineSinger]

Seriously??? 😐

[@newscoulomb3705]

@@HookLineSinger Seriously. It's also a felony to possess a "sniper scope," which is any optic with night vision or thermal capabilities. Just think how dangerous it would be if people could correctly identify targets in low-light conditions. California law makers are truly special.

[@HookLineSinger]

@@newscoulomb3705 makes me thankful to be in Alabama!

[@Zer0Edits00]

You mean a suppressor? Cuz a hearing protection device could be headphones 💀

[@newscoulomb3705]

@@Zer0Edits00 I said what I said. 😉

[@user-eg8hb8xt3j]

Suppressors …another thing to go wrong in the bush . Great idea

[@waynebrown2546]

A quick trick a friend of mine told me was to use nail polish around the screw heads. every time I take the gun out, I now look at the rings and the pic mounts for the nail polish to be intact, if something moves, the polish will be cracked.

[@SteveChishamSr]

Thanks for the information regarding light changing the zero

[@coolkidmandude1]

Regarding cold bore shots, I have a hypothesis in its infancy that I really want to test more. I picked up a garmin chronograph and decided to just chrono everything my buddies and I shoot, along with some other guns we get to use through our job (Bergara b14 and hmr in 6.5 cm, seekins hit 6.5 cm, dmr 556, and sp10 in 308, Marlin trapper 45-70, Christensen ranger 22 lr so far). I noticed the velocity of the first recorded shot was generally one of the closest to the average over 10-20 shots. I want to test this much more before I put any stock into this but perhaps taking a lot of time between shots to allow the rifle to cool would improve zeroing. This would mainly apply to hunting scenarios where having the best zero cold bore is essential, but also developing a dope chart closest to that cold bore shot’s velocity and average velocity would be extremely helpful. But in reality, most people don’t shoot well enough for it to matter, whether it’s abilty to adjust for elevation/wind, ability to create and use a stable position, rifle/optic quality and gear setup, or what I just like to chalk up to fudd lore.

[@PrecisionRifleNetwork]

solid informational video as usual! Ordered some turret tags - what a great idea...that I wish I would have thought of. LOL

[@Timberdam]

Very informative Jim ! Thank You .. Just read ottokite post and reminded me of a drifting zero on a GA Precision 300 WSM and couldn't figure the culprit until I took the scope off and one of my Premium rings had a hairline stress crack .. Called the company and he told me they had some metallurgy issues with a batch of rings and I returned the ring to them and they sent me a new one ... Back in business ... Hasn't moved again...

[@RobProbst]

People may be confusing clean bore vs cold bore. I have had many different rifles and especially mussel loaders that shoot horrible when they are clean. So maybe what some would consider a fouling shot is being blamed on cold bore

[@pablopenasco4254]

I remember Johnny’s Reloading bench had a little fan gadget that you put into the chamber and blow air down the bore to speed up cooling the barrel back to “cold” bore status. That helped him speed up the process when trying to fine tune his hand loads.

[@biggs8729]

Cold bore shift is absolutely a real thing, Although it is not necessarily something that is present or significant enough that you will see it in every rifle. I had an Accuracy International rifle in 308 with a night force scope in the night force rings and the first shot out of this gun was consistently in the 7 o’clock position between a half and 1 inch out from the rest of the group. After that first shot, the gun would shoot a half to 5/8 minute five shot group every time. Before I sent it back to Accuracy International for warranty, I had other shooters test the Cold bore. It didn’t matter who shot the gun. It was always in the 7 o’clock position a half inch to 1 inch from the rest of the group. The factory could not figure out the problem or wouldn’t tell me what the problem was. They ended up replacing the gun with an upgraded model.

[@jonathanrogers9961]

Hornady podcast #50 on group size is very interesting. Basically, you should shoot a 10-20 round group and use the center of the group as the center of your zero. and that group should be what you consider your rifle actually capable of.

[@jasonshults368]

10-20 shots? Maybe for Fudds. I use a 750 shot zero.

[@cypherthepro]

Hey Jim, When culling deer, after 2-3 shots we check the mod. Although, it happens you drop 4-8 in one salvo but try to not rush and if possible to keep in mind the heat is building and mod could shift. I am lucky in that my mod never moves when culling.

[@williamgaines9784]

You must use a heat shield/cover on your moderator, or you might regret grabbing it after 4-8 rapid shots.😮🔥

[@cypherthepro]

@@williamgaines9784 it's just wrapped in nice camo tape. It really doesn't happen often. The spigot mods seem worse for it

[@america2revolt]

I have a Ruger M77 Mark II .30-06 and I have only had to re-zero my scope on this rifle once in 30 years of hunting. And I have hunted with it every year for 30 years. I even have a fairly cheap scope on it. It is a Bushnell Trophy 3-9X40mm. The reason I had to re-zero is because I lost a screw gromet my sling and the rifle fell off my shoulder and the end of the barrel hit the gravel road!! OUCH!!

[@cwness4587]

Some good stuff again. Now I have check my guns again. Just when I thought I had all my guns dialed in. Good job Jim makes very good sense. CW

[@oncall21]

Great topic. One thing I have always done is have my action bedded and barrel floated and triggers set to the same weight.

[@tandtoutdoors5154]

I learn3d to purchase double luggage scope rings with tape in the housing. I also use the sun shade as what you said about the light impacting your zero is true.

[@Gunnybumper]

People mistake cold bore for clean bore. Cold bore has no noticeable effect on any of the hundreds of rifles I have shot. But if you have cleaned, even just a dry patch down the bore. Your first shot (and maybe 5-20 shots after with a full copper remediation) will be a flyer.

[@jasonshults368]

I've seen several guns that will throw a first shot well off the mark. Most of them have been lever actions.

[@JaronActual]

Cold bore shift is real. A primary cause comes down to how the barrel is made. As steel is being forged and shaped, it can build up internal stresses where different grain patches in the steel want to naturally flex some direction. If the steel isn't properly stress relieved, the barrel will bend itself one way or another when it heats up. The hotter and thinner the barrel, the easier it is for the internal stresses to flex it. The stories of early M16s shifting zero as they heated up are at least partly true because metallurgical processes have advanced greatly in the last 60 years. A barrel that was properly stress relieved during manufacturing should have minimal shift as it heats up, if any at all. But it's also important to remember that your groups will always open up as the barrel gets hot. Lightweight hunting rifles, those with thin sporter barrels, can start opening up after only a couple shots. I had a Creedmoor that could place the first two shots relatively close, but couldn't hold better than a 3" group if you fired more than three rounds in five minutes. So it's possible what one person thinks is cold bore shift is really just the barrel quickly getting hot and the opening up.

[@onebadjack1313]

The zero isn't "moving". All of that was within the cone of dispersion for that rifle and ammunition combination. Hard to watch

[@jasonshults368]

Looks to me like he doesn't know how to shoot off a bench. If I have shots 5 inches apart on my 100 yard target, something serious is wrong. Even the bargain rifles shoot far better than that.

[@SuperBman1221]

I always wonder as a white tail hunter isn't the first cold bore shot the most important as usually the first shot after hitting your stand is the most important

[@benjaminchristensen837]

Thanks for this video! Keep making more like it! Back to the basics

[@upnorthreloading2214]

I have found that, usually, what people call cold bore shots end up being *clean bore* shots. There is some aspect of their cleaning regimen (and, either alternatively or additionally, the barrel is sensitive to fouling) that makes the first, or first couple shots, different from the rest. After that, I would say that it's something you already touched on - the person's rest settling in, and it's affecting the shooting system (rifle and shooter) as a whole. From there, the onus goes more and more on the shooter, to all the other various points you talked about: parallax, the shooter settling in, etcetera. Another thing I'll toss in, although this isn't strictly cold bore related, I've seen instances where people who take too long to shoot experience point of impact shifts --- after firing several rounds, they leave the round to 'cook' inside the chamber, which can affect the combustion of the components and effect ballistics. I mention this not only because it's POI related, but also it touches on another subject you mentioned: environments. Beyond those broad elements of weather conditions and shooter/system error, it takes... something special for cold bore shots to be an actual, legit thing. We're in the day and age where manufacturing, design, and quality are pretty darn good, and you basically need *something wrong* to have cold bore shots. Thanks for doing this video.

[@buzzblitzer750]

Hello from Canada! Could you do a video on SCOPE RINGS alone? I find quite a difference between various rings, some close nicely around the circumference of the scope, while others have a slight gap even though they have been tightened to the recommended torque. I wonder when we get a large temperature shift, if the scope could then move under recoil. I shoot a custom 375 H&H magnum as it has been my favourite cartridge for 40 years. Between the several sets of rings I have, the ones that do end up with a slight gap always seem to be the least consisted and I’m not really sure why. The last time I used such rings was three years ago. The rifle had been zeroed with a new Whitworth barrel installed into the Mauser action ( also new). I took it hunting that fall ( within two weeks of zero) and also took a few test shots after the fly-in. Second day of moose hunting, a hot fall day and an easy 300 yard shot presented with no crosswind at all. I took the shot using a rest, and while it was still a decent hit, it was a fair bit forward and high. Later after recovering the animal, I shot another 200 yd group at the camp after the hunt only to find my zero had shifted three inches left and two inches high. After returning home, I changed out the rings and have not had the same isssue since. I knew it wasn’t the optic, I knew it wasn’t me, as I’ve put thousands of rounds of .375 down range over the decades and I’m very comfortable with the recoil of the rifle which fits me very well. I’d love to hear your opinion on rings, how you set them up, and your experiences. Cheers.

[@wesmatthew7860]

I have had this problem on one rifle ( light barrel) where the first shot on a clean cold bore the shot is way off. Then it comes reasonable in grouping with subsequent shots. I put this down as the first shot is on a barrel with no lubrication from the powder. The burnt powder does provide lubrication. Barrel walking is also a problem with light barrels.

[@deedraper9796]

Very comprehensive testing with outstanding information I have found that the most accurate hunting zero possible is to shoot cold bore groups to establish an average zero Right on good stuff mate

[@darrelbeach6585]

For a hunting rifle I really believe in establishing a cold bore zero. What was the shot spacing on the shots. Maybe use a laser thermometer and record the barrel temp for each shot. From what I have read cold bore variation can be affected by the barrel manufacturing process and stress relieving the barrel.

[@McgSpook]

There used to be a big thing where people were doing cryo treatment to barrels to relieve the stress. Never see it anymore so I guess it wasnt an issue. My little devil on shoulder tells me that what people are really seeing is cheap or poorly made barrels doing what they do. Someone like Remington or Winchester just never has time to do what a good gunsmith will do. So they have slop and runout issues galore.

[@esposb6710]

Here in Norway, we have mandatory practice shots. Minimum 30 of them spread over atleast 2 days before we have a practical shooting "exam". Every year. 5 outta 5 shots have to be inside killzone on a reindeer target. If we have problems zeroing in, we get help from our friendly neighbourhood gun and hunting guru ( he got 64 years of hunting experience and hangs on the shooting range every week )

[@arcli9ht]

This might sound stupid but aging of the fouling in the bore can do it too. Even if that fouling is just the oil after cleaning. The carbon absorbs water, the copper oxidizes, the oil evaporates.

[@splitpin1764]

None of my hunting rifles that were glass bedded had problems with zero shift. The Howa .223 i use would was very fussy with different ammo and would shift at different temperatures. A full action bedding job and now it is far more consistent, even though group size hasn't changed.

[@t3h8ar0n]

I remember reading a long time ago that you could eliminate "cold bore" shift by breathing into the barrel before the initial shot. If I recall it has to do with the level of moisture in the barrel. I have tried it with my rifle, and it worked for me. Get a straw, and shoot a puff of air or 2 down the barrel prior to first shot and see what happens compared to when you dont.

[@jimyeats]

5” POI change with a quart turn of the suppressor is definitely on the extreme side in my experience. I’ve had one gun (a Keltec RDB survival) with an absolute pencil barrel that has around a 4” POI change at 100 yards between suppressed and unsuppressed, but between suppressors only minor POI changes. Every other gun, suppressed, unsuppressed, different suppressors, exc, only around 2 moa difference.

[@kgchrome]

every savage rifle i have bought new has a ton of oil under the mounting rail. after zeroing, it would shft. removed the rail, cleaned and dried the rail and action, then mount again with loctite. the 338LM 110 even had mounting rail holes that went through to the action into the bolt area. any cleaning fluid used would wick into the hole and loosen the loctite. had to be diligent.

[@garyhosier4765]

Thinking about cold bore. I’m just an average everyday shooter. I work in a machine shop. I could see a rifle bore changing with temperature. Variables might be material of barrel, thickness of barrel, tempering of barrel, consistency of atmosphere during machining causing a less accurate barrel. Maybe the bore isn’t directly down the center all the way; ie; barrel thickness varies around diameter, the rifling is inconsistent down the barrel. I’m not a gunsmith or anything. Not even a machinist. I just work manufacturing machined parts, some thick some very thin. Some of our parts have 2000 lasered holes .025-.030 diameter. The part changes.

[@jamesmooney5348]

Jim, you definitely get a 👍. Good video.

[@gboutdoors5198]

nice I was really pumped for this video

[@NightSniper64]

Hey Jim, After reading several of the comments. There is another possibility that no one is saying. It's rarely thought of yet it happens. The ammunition. If you are shooting factory ammo a change in boxes different lot #s. Lets face it factory ammo is less dependable. Hand loads are usually more accurate and consistent. With that being said you can have a box of bullets for loading and change lot#s and their can be differences, just like powder and primers. I've run into this several times over the many years of handloading. There is no such thing as the perfect zero. The best we can do is the best we can do. Especially when there are so many things that are against shooters, some in our control and some not.

[@goinrich25]

In my experience, there IS a different in bullet impact between a cold barrel and a hot barrel, but unless you’re using the same rifle for hunting and competition, most people won’t be able to tell a difference out to about 300 yards (give or take depending on the caliber, MV, bullet weight, etc.). I don’t shoot competitively now, but in the past I’ve always used the cold bore method of zeroing for my hunting rifles and shooting various amounts of rounds at a time for competition rifles. Of course, barrel weight and thickness, action type, and action quality all have an effect on this. In conclusion (as with most things shooting), how much a cold bore vs hot bore zero varies greatly depends on a multitude of factors and there really isn’t one right answer.

[@8MM.PRC.HUNTER]

Great video Jim, good stuff

[@tikkamarksman]

A scope don't go backwards in the scope ring under recoil 💡 If it's creeping, it creeps forward >> But you are totally right it's a bad thing to mount the scope in that manner from the beginning 🤝 Greetings from Sweden 🫡

[@williamgaines9784]

A lot of people don't believe it, but it is physics. Each component moves in succession. If the scope rings are loose, or the base is loose, the rifle moves, then the scope has to catch up. The scope is not going forward as much as the rifle moves backward from under it - similar to the tablecloth yanking from under the dishes.

[@tonycanniffe2360]

Tack så mycket!🇦🇺

[@codyway7424]

Good job, you covered many potential causes of zero shift. Might want to address mirage causing the image that you see to shift. Usually 1/2-1 moa.

[@workinonitsteve]

Good stuff, great video 👍

[@brandon88271]

I had the same issue with the suppressor not tightened all the way. So now I have witness marks to prevent that.

[@mrs.vasquezz]

Just use a good mount system?

[@brandon88271]

@@mrs.vasquezz I'm using Yhm phantom qd it works great when tight all the way.

[@stevelinville3681]

Great video, I may have missed it but I didn't see anything on a fouled barrel vs clean bore, this can cause the first shot fliers.

[@frost8077]

Expert advice for those of us who are new to shooting. I feel like I stumbled upon gold with this one.

[@ReloadingQuest]

Great stuff Jim. Pretty interesting stuff.

[@ericc3327]

Cold bore shift is very real, especially for rifles that aren’t free floated. Thermal expansion in the barrel changes contact with the stock, changing the point as the forces of a bullet traveling interact in new and novel ways. Now you could say “just use only rifles that are floated”, which is fair I guess. But that is a limitation in picking the tool you want for the job. Knowing your rifle, and how it reacts, is important. I’ve had rifles I’ve sold for this reason, because their use case meant that multiple shots would require a warm barrel. I’ve had others I’ve kept, because they would never be shot very warm.

[@mrs.vasquezz]

No

[@McgSpook]

im not so sure. i can definitely see saying once its HOT that it has shifted. But from cold to say shot 4 or 5 it hasnt had time to expand or shift. Maybe the bigger issue, as you pointed out, is not being free floated. Putting variable pressure on the barrel is gonna make it do all kinds of weird stuff. No way to actually tell if the zero is shifting due to temperature or just the stock being flexed.

[@ericc3327]

@@McgSpook all depends on the rifle and cartridge how much it shifts and how quickly. But I’ve seen it happen, one rifle would consistently shoot about 4” lower after 3ish shots. And return to zero after cooling down. And if you waited 5 minutes between shots wouldn’t experience PoI shift. I could have tried bedding it for more consistent pressure, or relieving some high spots to get the contact more even, but just sold the rifle.

[@McgSpook]

@@ericc3327 im sure it exist in reality to some extent. but i think people that see large shift, enough to set your zero to a different spot, have something else going on and it its not thermal related. but thats just my thinking. im as crazy as everyone else lol.

[@leyderness3553]

What we were taught through training at the S.O's office, is after cleaning the bore of the rifle run a patch through it with a little amount of oil, then run a dry patch through it. That little amount that is left almost mimics the first shot that "dirties the bore. The "cold bore" shot drastically changes the amount of shift.

[@McgSpook]

I'm not sure i would trust that. No way for oil in the barrel to evenly dispersed or take the place of copper. Even after a good cleaning my last step is alcohol patches to remove every bit of solvent and cleaner that may have been left behind. Even a foul bore is still shifting until its gets enough rounds down it to lay in some copper. I wont trust it to stay stable until at least 5-10 rounds. Personally believe what most people think of as cold bore is kinda what you are explaining. The temperature of the bore means very little, the condition of the rifling means a lot. A "cold" bore that is fouled should not drastically change anything. ymmv

[@goodnewseverybody739]

Good info, makes you realize once you found the right ammo and zero it, there are still things to keep track of👍

[@txmarine7557]

Your group sizes will likely tighten up or spread out with inconsistent suppressor tightness. Just like using a barrel tuner.

[@stevechewning7741]

Excellent and very useful

[@suprema-sea_fishing]

On budget rifles, sometimes the rifle is not secure in the stock. This can be easily fixed with a glass bedding kit. I bought a Mossberg MVP 5.56 that was shooting ok sometimes but often had a weird flyer. Groups were all over the place. I was doing dry fire practice one day, and saw a point of impact shift in the scope (crosshairs would click over an inch or 2 when the hammer dropped). I got a $30 bedding kit off amazon, and used it to fit the action to the stock. Once finished, tried dry fire again, no more shift. That $350 MVP now shoots sub moa all day, and 1/2 moa often.

[@jasonshults368]

If you keep shooting that rifle all day, you are going to spend a fortune on ammo.

[@suprema-sea_fishing]

​@jasonshults368 haha, thanks for your concern. I stocked up under the previous administration. It is just an expression though, what i meant was it is now a consistent Sub Moa gun. And, it has killed hundreds of ground squirrels out to 300 yards with great accuracy. The only time it misses is when I misjudge the range or the wind.

[@TheWeirdedBeardo]

Bro at 12:22 in the Video you can see Jesus over your shoulder. I love that Christus statue. That warms my heart. ❤🤍💙

[@scottlaplante3675]

I agree with everything you said , however your zero is only great if when you shoot after zeroing the external variables / day time conditions are identical from whe you zeroed the rifle . I always zero then go hunting . Bullet impact is different even with season or temperature change .

[@gold_3]

great job!!!!👍👍👍

[@SilverbackSasquatch19xx]

I wouldn’t necessarily say the zero is off if it’s on when things are secure but off when things are improperly fastened, however this information is valuable, don’t go shooting with a loose muzzle device

[@poorfatman5317]

Good info 👍

[@VK6AB-]

There is no perfect solution. What works for me is a 5 round grouping at distance X, followed by a confirmation 5 round grouping at distance Y (for example X could be 100m and Y could be 200m). In terms of scope mounting, with your Sig Cross (or anything with a pic rail) - I avoid stand alone rings and just use high quality cantilever mounts. Moreover, any scope I mount is levelled and screws/nuts tightened to manufacturers spec. Also, I have a DOPE notebook which is invaluable. This recipe works well for me.

[@jamesdonop445]

Great video!

[@peterdmatthews7427]

Check mounts and trigger pressure too high, pulling some shots. I zeroed my Savage model 12 with custom heavy barrel and many mods to 1/2 inch five group, then drove 3 hours to a deer hunt. The mounts (rings) fitted by the gunsmith moved by the time we got there. When i got home, i found he had not bedded the pic rail and didn't torque the mounts. I use a case too! Cold bore is bullshit. I've been an f class shooter for years and its best warm with heavy barrel. Cold bore only affects thin barrels. Biggest issue people forget is custom trigger, trigger weight (1.11-1.15) and plenty of dry fire practice.

[@robertwatson818]

I have a very accurate .22. I too have observed this group shift in impact due to position change.

[@davidallen3139]

I’ve got levels on all my rifles, not having a level will probably be the main reason groups change place, it also explains horizontal stringing (other than wind). Try getting your gun set up horizontally and vertically when the landscape slopes, you have no chance because it’s impossible to see your cant. Cold bore shots in my experience tend to be shooter error, dry fire your rifle 2 or 3 times before the shot you will see your error and see it improve from shot to shot without the recoil of a live round.

[@Deerslayer1912]

I generally agree with cold bore being cold shooter. Also, zeros shifting due to variability in shooting technique is pretty frequent as well. If guns have a “cold bore” shot, I usually just assume it is a bad barrel. Not worth messing with and swap it.

[@jeffboldt4168]

I'm a mechanical engineer, so I overanalyze physics. When I watch shooting videos, it's obvious that the shoulder contact to the stock is below the center of the barrel, so there must be a tendancy to lift the end of the barrel. If I designed a rifle, I'd raise the stock, and therefore the scope so the recoil doesn't affect the aim. That would also put the scope closer to following the bullet drop (assuming you added a tiny shim under the bottom ring). I think when I was a kid (Leopold? Redfield?) made a scope mount that would let you look below the scope to use the iron sights for close shots. Might even allow adding a mini-Red Dot under the scope. Thoughts?

[@jcjustice3786]

👍👍👍 great info

[@stevej2120]

Those of us that hunt with our dad’s or grandpa’s rifle have to deal with wood stocks that may change POI when the weather changes. We take them apart and clean them after hunting in wet weather and then re-torque the stock screws by feel. Usually not enough movement to cause a bad shot out to 300 yards or so where the vast majority of game shots are taken. A miss or poor shot placement can almost always be blamed on the shooter, not the rifle. Sometimes its an error in execution. Sometimes its an error in judgement.

[@randyjustin4408]

Cold bore that’s more than 1/2 moa is barrel that’s not made right, had a bergara HMR that they warranties and replaced the barrel for me. It was shifting 6 inches from cold bore over a 4-5 rd shot string

[@jeffward8278]

In my opinion, using a hard case, people usually put the gun in upside down. When they pick the case up by the handle, the gun is carried upside down. The weight of the gun is weighing down on the scope. I dont know if that could change impact or not.