Understanding Muzzle Velocity

[@L0NGRNGE]

glad to see you back posting stuff bryan.

[@longrangehunter6393]

Absolutely loving the content Bryan, thank you for doing this

[@rickbrown9523]

The data-based approach is much appreciated and hard to find elsewhere.

[@GetMeThere1]

I'd like to hear a discussion about BC corrections vs MV corrections.

[@aronph1]

This. @Bryan Litz Ballistics

[@JavierMoncadaIrias]

Yes! That would be highly appreciated.

[@BryanLitzBallistics]

Agreed, with better chronos now, it's questionable if the slight remaining error is due to MV or BC. We're working on better ways of interfacing this in the software, but the discussion about launch dynamics in the video is one reason for this observed issue: "I'm using the MV from the Garmin, which everyone regards as accurate, and I'm using a CDM or BC from the AB library, which are all derived from Doppler so that has to be right. So how to I correct error between my predicted and observed trajectory?" Often times, this is caused by a launch dynamic. As explained in the video, your (accurate) chrono reading may tell you 3000 fps, but a launch dynamic can easily 'rob' 30-50 fps or more in the first 100 yards. To the long range trajectory, it looks like the MV is 30-50 fps lower than measured, and you have a mismatch. You 'could' make a correction to the entire BC or CDM to line you up at some range, but the trajectory error at long range isn't in your whole CDM if you have a launch dynamic (technically the CDM is wrong by not accounting for the launch dynamic for the short period where drag is elevated). In that case, what I recommend is to lower the MV input, basically true MV to your observed trajectory, and trust that's your 'effective MV', which accounts for the launch dynamic. All of this is a challenge because you don't know if you have a launch dynamic. Maybe it could be tested for by roundness of bullet holes at 5-25 yards... like tuning a bow by shooting thru paper...? Again, we're working on better ways of managing this but this is the current state. -Bryan

[@GetMeThere1]

@BryanLitzBallistics Thanks. This video is really the first time I'm hearing about "launch dynamic." It's an interesting explanation.

[@JavierMoncadaIrias]

@BryanLitzBallistics Well explained. Thanks!

[@Longrangelab]

Thank you for the education Bryan.

[@LittleCrowGunworks]

Well at least you're watching good stuff on your days off.

[@EagleRun23]

Dude. Amazing video. Thanks for nerding out for us. Love it.

[@fermentillc]

This video was an amazingly useful applied guide to ballistics. I see what you where doing for 13 yrs. Very well done and thank you for this.

[@jamiekromrey8223]

An absolute Masterclass. Thank you!

[@takatir]

Thank you! the Garmin is a real game changer, I always take it out on the range, it allows me to discover and understand many things.

[@DocBacon]

Thanks, Bryan, for getting such good content out there. Even higher thanks for attending to all the questions your content creates. Please keep it coming.

[@davidblaauw1806]

Fantastic vid Bryan, we are privileged to have access to your knowledge & experience, thank you!

[@253hammer]

Outstanding! Thank you for this

[@Ooogs-h1i]

Loving that you're putting your knowledge out, thank you! Hope that you continue to make more videos!

[@seanbalser9468]

Keep them coming Bryan!!!

[@rifleman1873]

What a valuable presentation. Thanks!

[@rickervine]

Thanks for the info!

[@gabenelson8508]

Thanks for the great explanations.

[@Reloadingallday]

Great video, Bryan!

[@DRHODES1979]

Absolutely love this stuff! I've read all the AB books and have listened to all the podcasts, but I love seeing the new content you're releasing on KZbin!

[@wvlongshooter3912]

Invaluable information!!!! Thanks!!

[@ericbennett1253]

I use the Garmin now but I had the same experience as you with the Magnetospeed I was using prior. I would diligently mount it close/parallel but at 6:00. It seemed to group the same as without it, however the group was "deflected" close to 1" high at 100yds. Your Left/Right mounting appeared to do the same thing but with more spin drift affect I assume. I rarely wanted to hassle even mounting it so I agree with what you said about the Garmin being easy to use "at all times" is a game changer.

[@BestICan]

Thank you, Bryan!

[@rsvr62]

Thnx. Even if I've scrutinised your literature there are always some new aspects disclosed - especially wrt MV truing. Also like your illustrations. Much appreciated.

[@lancewunsch302]

Wow, excellent idea.

[@1shotbarbeque881]

Finally it has been explained to me perfectly. Thank you

[@ChrisSmith-wz4cc]

"AWESOME" Info Brian Thanks for sharing your knowledge

[@yuxuansun8271]

PLEASE MAKE SOMETHING ON BARREL HARMONICS/LACK THEREOF❤❤❤❤❤

[@bored31a]

I love the hairsplitting accuracy to this content! Just when I thought the shooting/handloading rabbit hole factors couldn’t get any deeper!

[@nicoharris2571]

Awesome vid. Hope to see more content like this!

[@MrNiceKnife]

Great information. Thank you.

[@justinrush6620]

Great video thanks Bryan

[@Nonedw]

Welcome back fantastic video

[@BryanLitzBallistics]

Thank you!

[@youngsmith5647]

thanks for sharing the great video, love it and learn a lot from you.

[@masonmcneill3969]

Love it, keep them coming!

[@leaningfree]

Hey, that was a fantastic overview of MV. Was especially interested in the bullet wobble possibility. Gracias!

[@OzkMtnDisciples]

First time I have come across your channel, and I'm sub'd. Thank you for the break down of a ton of data and knowledge. Not that anyone can control it one way or another, but I really appreciate that your voice isn't annoying/painful to listen to 😆 If I could submit a video request, I would ask if you could do a video on how different a 25-06 is from a 6.5 creed. In terms of trajectory, wind drift, and terminal performance at range.

[@josephhomen]

Thank you for everything you do. I’ve really learned a lot from your books and the videos! For years I figured the POI shift from the magnetospeed was to do with something like that.

[@Godfryness]

I would love to hear your opinion on the new Caldwell chirp radar crono vs the Garmin

[@westdesertwheeler]

Great content man

[@Kitchingfamily-ci3wq]

Thank you.

[@bpm990d]

Decades ago I shot a few Palma matches with Berger 175 VLDs out of my 13 twist rifle. It shot surprisingly well, but I didn't know at the time the about the "coning motions" as discussed in the back of the Sierra manual. It shot small groups and good scores, but I think the BC was probably compromised to the point that it was a wash with 155s (2155s) in terms of wind drift. The Berger calculator gives it a SG of 1.16. LoL.

[@BryanLitzBallistics]

Yes, you likely were getting a compromised BC with those bullets in that twist. Nothing a few more clicks won't handle!

[@bpm990d]

@BryanLitzBallistics I think I had a 440 and a 442 with those 175s. My best Palma was a 447, but that was with 155s, so the Bergers shot acceptably well. It was a fun little experiment, but I would never do that today.

[@williamleonard8998]

Excellent info

[@michaelhill6451]

31:01 Agreed. I also don't believe the "barrel harmonics" theory of precision. Looking at a gun firing with a slow motion camera it is pretty clear that the barrel doesn't move until after the bullet has already left the barrel.

[@tkssusa-ri9rj]

Brilliant. Now to translate into French for a friend - I don't think auto translate captions will suffice here! Thank you very much

[@HOG-cn8zd]

Garmin typically captures between 15-20 yards. There's a manufacturer's settings where you can see where it captures each shot, pretty neat.

[@BryanLitzBallistics]

Thanks for adding this!

[@johnseptien3138]

Many head scratching moments resolved in one video. Amazing! Our educational system is lacking in the field of applied physics, where were you when I was in school Professor Litz? Probably not born yet!

[@scottschnd6620]

Very informative. I see 10-20 fps difference between the MagnetoSpeed to the Xero velocities. Now I know how we can test the MS to see if the spacing matters and can get closer data between the two. The Garmin just seems to have it figured out.

[@randomidiot8142]

I recently had a xero/msv3 side by side and it was ~10 fps difference, occasionally less. Sometimes the high reading would alternate from ms to xero. With other chronographs the differences didn't swap 'leaders' and the differences were consistently either + or - on any read. More observation required.

[@BryanLitzBallistics]

"More observation required" is often where I'm left too! In the case of the test you described, you see a difference, but how do you know which is more 'true'? One indication of this is, the chrono that indicates the lower ES/SD for the same string of shots, is likely the one with the least instrumental error. And in the specific case of the MS vs. Garmin, I can tell you from my testing that the Garmin is your 'truth' instrument in that case, and most of the difference you're seeing is error in the MS. Take care, -Bryan

[@scottschnd6620]

@BryanLitzBallisticsthank you for that clarification I will review the data and I am in agreement the Garmin likely giving me the truth

[@jasoneastwood1191]

So when using my Garmin Xero, what distance do I plug into my AB solver for the “muzzle velocity” measurement to account for the velocity decay over said distance?

[@gmoua1234]

Love statistics!❤

[@Gideon94NC]

Thank you Mr. Litz! Can you cover powder burn percentages (% of burnt) & rate; and their correlation to initial muzzle velocity? Edit: added &, ;, (% of burnt)

[@alexandrmp1812]

Thanks for your work! About "truing MV": to my mind there are a lot of bad determined factors which can provide low or high impact when you're shooting on long distance. I think it's difficalt to specify all wind and weather conditions throug all long traectory to the calculator. And there will be some rough calculating in the calculator. I think when you're shooting on one range with it's specific wind and weather condition and on other range the "truing MV" can be different for one and other conditions. And what to do? What do you think about?

[@BryanLitzBallistics]

You're correct, many things can affect your MV calibration. Best to learn and apply best practices for isolating MV as the only variable by carefully measuring and inputting all variables of the environment including azimuth and latitude to account for Coriolis so that small error doesn't get baked into your MV calc. Part of 'best practice', beyond taking care in all ballistic inputs, is to select a range that maximizes your resolution of MV truing. The idea here is you want to maximize the drop in relation to your group size. So at 400m, drop isn't very much in relation to group size, maybe 2 MILs drop and 0.3 MIL groups. But at 1100, where your drop is closer to 10 MIL and your group is still probably .4-.5 MIL realistically, that's a much more favorable ration of drop to group size, so resolution of MV is better. But if you go too far, you get into transonic where stability effects can cause less-repeatable drag on the bullet, which results in uncertainty in the calc'd MV. So you're looking for that sweet spot right before transonic, about where you're bullets' slowed to ~1340 fps (Mach 1.2), to True MV. Of course the wind is a challenge; you can manage the vertical affect of Aerodynamic Jump by giving your solver the right inputs, but if there's vertical winds at play... now you're into guessing territory. It's best to avoid truing MV in the presence of vertical winds, or if you have to do it, note it as questionable, and repeat as soon as you get a chance to shoot in more favorable winds. Take care, -Bryan

[@DanielReyes-hz1qk]

There are apps and software that take environmentals into consideration when setting an initial zero, and those seem to do much better at longer ranges with varying conditions, assuming you're feeding it good info to begin with. Not bang on, but a whole lot closer than would otherwise occur

[@BryanLitzBallistics]

It's really only important to account for environmentals for longer range zeroes, like way beyond 100. If you zero at 100 yards or meters, the environmentals don't affect your zero nearly as much and you don't need to enable 'zero conditions'. But for longer range zeros, like 600 yards, absolutely you need to know the environmentals that zero was established in because atmospherics affect your long range zero much more than a short range zero. Take care, -Bryan

[@wormydog1724]

Please keep making videos

[@mathieulaforest1674]

So interesting again! Been thinking that my magneto setup with it attached to the stock on a tube was not affecting the bullet..... I was wrong.

[@johnbyrne1022]

Something I've always wondered about with this stuff: do changes in velocity affect where rounds land laterally as well as vertically, and how much? The way I see it, barrels whip and there's no particular reason why they would only do this vertically. Everything in the chamber is symmetrical so there's no such thing as "vertical" as far as barrel harmonics are concerned. So it whips around in 3 dimensions like a skipping rope. But then if the velocity varies randomly, then the muzzle will be pointing in a random direction when the bullet leaves the muzzle. Thus you would get a circular pattern if gravity wasn't a thing. Add gravity into the mix, then it should be like a circle that's stretched downwards. Increasing the variation in velocity should make it wider as well as taller. I never get to shoot at long ranges so I have no clue if this is what actually happens, but I would like to know.

[@DogOnAPhone]

Harmonics don’t exist in any meaningful manner to affect precision. Never been shown to exist in reality, just in the simulations of people selling products that claim to fix harmonics

[@johnbyrne1022]

@@DogOnAPhone Interesting! I was assuming it was a widely accepted thing.

[@BryanLitzBallistics]

For most conventional bolt action rifles, the configuration of the recoil lug at 6:00 is what sets up the vertical plane for recoil to torque around. Think about it like, the barreled action wants to come straight back, but it's anchored, so it tries to rotate around that anchor, which is muzzle up. So most shooters who talk about tuners are talking about tuning in the vertical plane because that's the direction the recoil action is around the lug. I had a 308 win on a Rem 700 that I used in early BC testing. I was getting a look at the relative zero at 100 yards for different ammo types loaded with bullets from 155 to 240 grains. With each increasing weight, I observed, as expected, the POI dropped on the 100 yard target due to the MV being lower for the heavier bullets. But what also happened is the groups didn't just drop at 6:00, they followed a line at about 8:00, shifting more to the left than down. I never got to the bottom of it directly, but my analysis is that's likely the effect of a recoil lug not being in equal contact (from left to right), and hitting one side harder than the other. In that case, there would be a lateral component of recoil, in proportion to the magnitude of recoil, hence the groups walking to the side. So that might be a mechanism for recoil dynamics and bedding to give you a lateral POI shift, but note it has nothing to do with harmonics, just the movements and rotations from recoil. Harmonics come after the bullet has left the muzzle. Take care, -Bryan

[@johnbyrne1022]

@BryanLitzBallistics Thanks for the detailed answer!

[@andyhb572]

Another question please: Does the plane of the muzzle and plane of the radar sensor need to be maintained throughout a string of shots? I am thinking that MV must be 'back calculated' and therefore an assumed distance from the bullet to muzzle to make the geometry work ? If the radar is measuring a few feet ahead and the shooter moves the relative position of the muzzle back/forward a few inches will that introduce errors in reported MV ?

[@BryanLitzBallistics]

technically yes, but the amount is very small over the few inches you're moving. Refer to the chart in the video that shows you how much velocity you lose between the muzzle and skyscreen chronograph. A decay rate of 0.6 fps per foot is a typical value. So you're not picking up much error by moving around a few inches.

[@denshakespearemint4652]

Thanks!

[@RicardoGonzalez-ug6xm]

Dam !! Bill Nye ain’t got shit on you 😂 you sir have mad knowledge…thank you for this info 🤘🏽

[@misterlewgee8874]

I'd like to hear your thoughts on radar chronos that calculate BCs Thanks

[@BryanLitzBallistics]

I don't think they do a good enough job for long range. Several reasons: 1) To whatever extent you have a launch dynamic at the muzzle, the chrono is only seeing the bullet fly with a compromised BC, which isn't representative over long range. 2) Even if the radar makes a perfect measurement of BC, with no launch dynamic, you still have a problem of that BC only being valid at high speed. Remember BC changes with velocity as the bullet goes down range. To have a BC work effectively for long range, the BC needs to be measured, averaged, over long range in order to accurately model your trajectory at long range. This problem is somewhat mitigated with BC's referenced to the G7 standard as opposed to G1, but there's always some bias for it being the BC at 'high velocity' vs. average velocity. In the early days of the Labradar I calculated BC's from the track files it makes on every shot. The results were very different than the BC's I measured over long range for the same shots. For example, over long range I would see a G7 BC of like 0.305 with an SD of under 1%. But based on the Labradar data (only out to 100 yd), the same string of shots would have an average of like 0.283 with an SD of 3%+ due to the launch dynamic out of the muzzle. Our big radar often shows the BC in the first 100 yards to be lower and more variable than it settles out to at longer range. I realize it's tempting, but you're just not getting accurate enough BC's for long range work. An exception may be air guns. They may track far enough to get an accurate enough BC for air gun slugs, but at those speeds, the BC is less important than MV anyway, so that may be an application where you could use the BC from the chrono with accuracy but I haven't tested them for this personally. -Bryan

[@MegaGouch]

The launch dynamic subject is very interesting and explains a lot of what people see/have seen in the past. Question is what should we do when we see a difference between trued data and measured data. 22lr at long range never seems to be as simple as centrefire (advertised BC + chrony) and needs a bunch of truing and fudging of the numbers to fit a calculator. If you could collect enough data do you think you could find a trend, thus a figure for your launch dynamic? Maybe I’m just unlucky but I’ve found 22lr at disatance (150yards+) to be a complete nightmare compared to centrefire.

[@CWC-e2m]

Very informative lecture. Thank you. I wonder if you would consider doing a lecture on the effect or impact of suppressors on MV and precision? The shockwave results from the magneto speed were interesting and begs the question for suppressors. Thanks again.

[@BryanLitzBallistics]

I had the same thought about suppressors. Will likely be looking into this. Only so many hours!

[@handyman1001]

Have you tried the new Labradar yet? Looks to have some good features. Waiting for mine to arrive. Really appreciate your description of the benefits of truing MV.Thanks for the vid!

[@jmm6990]

Hi Bryan, great video but I have to disagree with you (31:40) regarding the barrel harmonics not happening before the bullet leaves the barrel, the speed of sound in steel is so high that the shockwave travels the barrel back and forth many times before the bullet leaves.

[@BryanLitzBallistics]

Technically you're correct. There are trace vibrations in the steel from the firing pin strike that are present while the bullet is in the bore. Those tiny vibrations are negligible in comparison to the PULSE created by the chamber pressure spiking to 60ksi, and the entire rifle being recoiled into motion. I'm not aware of any direct evidence of natural harmonics in a rifle barrel, having a measurable effect on precision. Many indirect connections and anecdotes, but no direct and repeatable evidence.

[@jmm6990]

@BryanLitzBallistics I would say that the pulse created by the explosion travels the barrel back and forth many times before the bullet exits the barrel, I know you don't believe on the "harmonics" and tuners topic because you don't have yet an empirical way to measure them but I just believe the target, and the target shows me that I can influence the results by hanging a weight at the end of the barrel.

[@BryanLitzBallistics]

I agree that hanging weight on the end of the barrel will change point of impact, and maybe even average group size. We just disagree on the mode of causality. Some believe the causality is thru the effect of the mass on the barrel harmonics. I believe the effect of the mass on the barrel is the simple, direct, first order affect of mass/inertia. The weighted muzzle will move less in the same time as compared to the un-weighted muzzle. A 'less moving' muzzle is good for precision. I developed the Theory Of Precision for Guns: TOP Gun theory, which predicts the average precision of a rifle/ammo combination according to the mass of the rifle and the kinetic energy made at the muzzle. Light weight guns shooting high energy ammo are worse case scenario for precision, while heavy guns with light bullets/low energy are best case. The theory is rather course, you can think of it in 1/4 MOA increments, but it gives you something to compare with and see if you're rifle is beating the expected trend for other guns like it. If you're not at or better than the TOP Gun prediction, you are likely able to improve by fixing something. If you're at the prediction or better, that's an indication that you're into a good combination and should leave it. TOP Gun theory is explained in greatest detail in the book: Modern Advancements in Long Range Shooting Volume 3.

[@kalindanley2843]

Wait... Why didn't you talk about the Caldwell and Chirp! Damn I really wanted your take on the Chirp with the Caldwell.

[@quentinvaldeyron7827]

Would love to know what kind of professionel Radar your team is using and how many points you are collecting along the way to the target. I bet you can read the full path of your bullet, but I am interested to know what it is. Thanks for the video, again a reference in attention to details.

[@BryanLitzBallistics]

We use the Infinition 29015 Doppler Radar. At max, it could probably ping the bullet several times per foot, but data that dense is overkill so we dial it back and still get basically a continuous track of velocity decay. It's cool seeing where the bullet has dynamics, like near the muzzle (sometimes) and transonic.

[@The4GunGuy]

What is your take on truing DOPE out to distance? Some say adjust MV only, others say MV out to 500 yds, and BC beyond that, but I'd like your take on it please (I use your CDM and have had great results with only adjusting MV out to distance)? This question is specific to PRS style shooting, where we don't generally go beyond 1,100 yds. Thanks. Great video as usual Bryan!

[@BryanLitzBallistics]

I agree with how you're doing it; use a CDM and true MV, but further than 50. Any PRS rifle should be supersonic to at least 1000 yards, best to true MV at the extent of supersonic range where you have a lot of drop to resolve MV accurately. In the event you do this, and the MV doesn't match a Garmin, it can be due to the launch dynamic mentioned in the video. That's if the chrono reads faster than what you true MV to be. If the chrono reads lower MV than what you true to, there's a different problem (not launch dynamic).

[@The4GunGuy]

@BryanLitzBallistics Thanks for the response. Can you please define "different problem" if the truing MV is high than the chrono reading?

[@BryanLitzBallistics]

Yea, I mean just literally anything else; scope tracking error, shifty zero, wind, AJ, mis-ranging target, mis-identifying impact locations, not accounting for Coriolis in the MV true if shooting East or West... There's any number of errors that can land you on a MV that isn't accurate but most top shooters are pretty good about isolating it down to MV. It's when you've literally done everything right and there's still a discrepancy, many think it has to be error in the CDM which is possible as all guns are different (though few are 'very different' from our CDM's which are averaged out of many rifles). But sometimes you can see a discrepancy even with a perfect CDM, in the case of a launch dynamic.

[@The4GunGuy]

@BryanLitzBallistics Thank you so much Bryan.

[@jtstarky]

31:27 who else started looking for the slack notification on their computer?

[@andyhb572]

Excellent stuff as usual Bryan. A question on "Truing" if I may. Will launch dynamic losses be reasonably consistent over different environmental conditions - ie once trued is it a reliable MV to adopt for that ammo type? Is it also best to true with different distance measures or does that not matter enough to make a measurable error?

[@BryanLitzBallistics]

Good questions! It depends on what's causing the launch dynamic. If it's something permanent and unchanging like a crown, it's likely the same all the time. But if it's caused by something like carbon build up on suppressor baffles, it may come and go as the carbon builds up and breaks off. Launch dynamic is an unfortunately difficult variable to know about. It's the reason why you can sometimes shoot with a good chrono, and CDM, and still hit low at long range. Guys think the CDM needs corrected, and sometimes it might need tweaked for their gun. But it's also possible that they have a launch dynamic that's bleeding velocity more than the solver knows about, and that's why you're hitting low. In that case, it would be valid to run a lower MV in the solver than what your chrono is showing, to account for the launch dynamic. As for distances to true... it's not necessary to true MV at multiple distances. The best thing is to do a good job truing at the extent of supersonic range, at the verge of transonic, where your bullet has slowed to around 1340 fps. Truing MV at shorter distances is not resolving MV as well as when you true it at further ranges, so the furthest range MV true is the only one you really have to do. Truing at shorter range just gives you a lower resolution estimate of MV.

[@bryceeverett]

Thanks for another great video. Maybe I missed it, but how accurate is the Garmin from what you found. Also, you didn’t mention the Shotmarker system. I’d love for you to touch on it too please as to how it compares. Thanks!

[@BryanLitzBallistics]

The Garmin is extremely accurate, to the point it's difficult to be sure of a 'truth' measurement to compare with when they're within 1 fps. The velocity indicator on the Shotmarker system though, is incredibly inaccurate. The spacing between the mics is not far enough to resolve MV accurately. It may be useful as an indicator of variation, meaning the shots it indicates as fast in relation to the group probably were fast, you just can't hang your hat on the absolute number it reports.

[@iluvstrats2864]

"god forbit thew internet" that bubbas pissing hot hand loads.

[@markalambert78]

Brian, question, have you done a test testing the same piece of brass over and over for repeatability? Maybe you have, just curious to see if im barking up the wrong tree for my sd journey.

[@BryanLitzBallistics]

Yes. There's no magic there. I've shifted from believing that brass consistency is highly causal to SD's. In my experience, getting reliably low SD's is about pairing the right powder and primer with the barrel length and bullet you're using. If you get that combo right, you can see nearly single digit SD's even with (carefully) metered powder charges vs. weighing to the 0.1 gr, and then when you do weigh to the 0.1 grain, you're into SD5 territory. To minimize SD, look at the top 1/2 of faster burning powder options in the load manual. If you have a short barrel (22" or less), look for the top 3 fastest burning powders in the manual for your bullet and work with them. You'll not reach the max fill ratio or max average velocity, but it's where we see the smallest SD's. It seems when the powder is 'eager to ignite and burn', things get kicked off in a more consistent way. Good luck minimizing SD's, it's a noble quest! -Bryan

[@markalambert78]

@BryanLitzBallistics I'm between 3 and 5 SD with 5 shot groups. Weights of brass seam pointless but do ball park. I believe the walls of the brass are inconsistent (volume to air ratio kind of like an aerosol can)so I'm in the process of recording what each individual brass gives me for fps out of the same rifle and same individual brass. So each brass that gives me between 2675 and 2680 out of 100 brass, I will keep aside, then reload that batch of say 20 to the same weight and I'm having extremely impressive results. I've been developing my old ladies Tikka and trying staball powder and the granulars of powder are half the size of h4350 so I can get .02gn accurate. But 0.1gn can have dramatic velocity inconsistencies. Upwards to a difference of 20sd. I'm still playing with it but find it quite fascinating to be down to 3sd. I'll go down this road a bit farther, I am cleaning I'd of necks with wire bore brush and using a mandrel, just not sure if I'm fluking out and if others have tried this on a grand scale. You guys do lots of this kind of stuff.

[@BryanLitzBallistics]

3-5SD is rare territory! At that point, you're likely to see variables affecting your SD that you might not think of, such as velocity migration, how broken in the barrel is, barrel temp and how long between shots, temp affect on primer... Here's one that's more likely than others... We did a test one time coating bullets with various lubricants to observe effects on MV, pressure, fouling, etc. It makes a huge difference, like 100+ fps when you coat a bullet with grease or oil. So that got me thinking, what about the residual oil on your fingers when sorting, pointing, or loading the bullets? So we tested a string of 10 shots where we handled one bullet with oily fingers, and it was a noticeable velocity outlier from the group. So that's one thing to check. That's just one example, but my bigger point here is that when you're trying to get as deep into single digit SD's as 3-5 fps, there gets to be outside influences that can come into play that you don't normally think of. Accuracy of the chrono used to be a big one but radar chronos have taken care of that.

[@markalambert78]

@BryanLitzBallistics yeah I've switched to the garmin from my magneto. I'm gunna shoot out the remaining bullets, and retest in a week or two. I have fluked out way too many times to trust small samples, but I'll let you know my findings later. I'll do this several times to see if it repeats a few times. The lubed/greased bullets is something I would have never thought of either. Cheers.

[@iMakos101]

In English what am I looking for when determining if the fps of a load is within a click. SD , es or half the es?

[@BryanLitzBallistics]

Neither, it's the average. The analysis that talks about being 'within a click' is saying how much error you can have in the MV you input into a ballistic calculator, for that calculation to be within 1 click of actual. So if your actual MV is 3000 fps but you have entered 3020 fps into the ballistic program, that 20 fps error will equal 1 click of error in trajectory prediction at some range. That's what the analysis is showing; how many fps of error in MV will result in 1 click of error in trajectory prediction according to range.

[@randomidiot8142]

I think the biggest issue with the Labradar was not the detector itself, it was the design that lacked a visible laser slaved to the detector. It was a known issue for how long and labradar couldn't put a visible laser in it so customers didn't have to resort to mounting red dot optics to them? And then Garmin comes out with the xero and all of a sudden labradar has a mini also? Nah, screw them. My shoulder fell victim to their nonsense when it refused to read .50 cal bullets from my rifle but it would read the same bullets at the same velocity from a different rifle fired at the same target. Alternating side by side, still wouldn't read. Nonsense.

[@robinireland810]

Bear in mind that if you mount your Garmin Xero to your firearm you’re invalidating the warranty.

[@aronph1]

So I'm doing ladder tests. Every test. Every bullet. Every gun. ALWAYS shoots worse groups with the best ES. When I get to a charge where the groups are tight on paper, the ES's are shit. Now what? Load the good ES loads or load the good GROUP loads?

[@BryanLitzBallistics]

That is a very common observation and question I've asked myself when faced with the same results. The way I think about it, is to consider what's most important about the shooting goals, and what affects it most (group or SD). This basically comes down to how far you're shooting. Out to some range, you'll be better off with the smaller groups, because it takes distance for the SD to hurt you. But at longer ranges, the higher SD will spread your group out, making it even bigger than the load that had a smaller 100 yard group. So, if the main purpose of a rifle is to maximize hits at the furthest possible ranges, it's actually logical to go with the lower SD and bigger 100 yd group, because the group can actually be smaller at distance. Exactly where that break-point is in range depends on the relative size of the groups and SD's between the loads. If the SD is only a little worse but the group is much better, the cross-over range will be further out. The bigger difference there is in SD, the shorter range the advantage will cross over. Hope this makes sense, it's how I think of it. -Bryan

[@FOCUSCOMMITMENTSHEARFKINGWILL]

This actor skipped vertical overlap. This is when several tenths of powder shoot the same vertical. This video is fraud.

[@mattc1248]

Are you dumb on purpose?

[@Josh-uf1rv]

I love coming to the comment section to find people that think they know what they’re talking about. And try to disprove Bryan without anything to back it up.

[@ericbennett1253]

Since you obviously don't know who Bryan Litz is, YOU are the actor my friend. There isn't a more knowledgeable or respected authority on ballistics in the world. I'd be interested to read your books too though. Have a link?