Mail Call Mondays Season 2 #35 - Optimal Charge Weight (OCW) and Optimal Barrel Time (OBT)

[@MrNiceKnife]

This video was pure gold John. Excellent advice with self preservation as well.

[@RetrieverTrainingAlone]

The sill is desired and important because powder performance may vary with temperature and throat erosion. By using a powder charge within the sill, these effects may be minimized. However there is variation at any specific load because the scale accuracy may be +/- .05 gr, there is variation in hand loading components, the chronograph accuracy may be +/- 5 fps, etc. So it is possible to get an "artificial sill" due to inherent errors in measurements and hand loads. These variations are not accounted for due to a sample size of 1 for each powder load in the 10-shot OCW method. One approach is to shoot the 10-shots from low to high powder charge, then repeat for a sample size of 2 by shooting the 10-shots from high to low powder charge to confirm that the sill is not "artificial". Or shoot the 10-shot OCW each day for 3 days in a row to see is the sill "artificial" or is is consistent and real?

[@rwreter]

Dan is a great guy!! Got to shoot with him a couple of months ago and has helped me a lot with OCWs. Great coverage John!!

[@toast47624]

As a competition shooter....well done. It was good to hear how someone else interprets the application of these methods. I know and you know that there is a bit more detail but for those just getting into this it was a very good presentation. Load development is an imperfect science but the use of Quickload and OCW and OBT greatly reduce the total workload.

[@FuelTankerMan]

Great job on this... I like the 44.6 grain tentative conclusion. We've found "scatter nodes" where accuracy opens up wildly interspersed at 1.5% intervals along the continuum... and with an apparent scatter node here at 45.2 grains, that would point back toward 44.6... and forward to 45.8, which as you point out is pushing too much pressure most likely. Anyway, I enjoy your videos, and figured I'd better leave you some accolades on this one--very good job. Dan Newberry

[@Strelnikov10]

Hands down, the most valuable collection of knowledge on youtube. Thank you!

[@1911jk]

One method I use to keep track of shots using a ladder is to use a permanent marker and color the bullet from the ogive to the meplate. Each load gets it's own color. Then I shoot the ladder on white paper. Each bullet wipe on the target will have the color you used. It saves lots of time with having to go down range with each shot or setting up a video camera. Great video as always!!! Keep up the great work.

[@Ensign_Cthulhu]

My decision to forego Monday evening reloading for the delights of a beer has been adequately rewarded!!! You've provided me with timely food for thought as I head out to the shed tonight and dig out the Varget & the 215gn RN moose-smashers.

[@lmt200ish]

Yes that would help as long as the round is in the chamber to warm up a little. Thanks

[@Ensign_Cthulhu]

Sources include the Textbook on Small Arms 1910, which is rather esoteric and hard to find, but from memory the long Lee-Enfield (30 inch barrel) would tighten up at about 1500 yards with service MkVI ammunition and the SMLE at about 800. The updated 1929 edition goes into great depth on the factors which affect ammunition performance, though it's mostly with reference to cordite rather than modern powders, and if you've got a good head for maths it makes for interesting reading.

[@gouldgibbonsiii4742]

In case you were not aware, no need to try to tumble the sharpie off, just a quick wipe with acetone will take it right off, completely too.

[@8541tactical]

👍

[@drmaudio]

Like a tuning fork, which always rings the same note regardless of how hard it is struck, the amplitude will change with pressure, but not the frequency. Shifts in amplitude will not effect the desired timing.

[@davkenrem]

John, Thanks for doing this video. It was very informative. I tried it today and here are my results. Video Response: Mail Call Mondays Season 2 #35 - Optimal Charge Weight (OCW)

[@Tsorenson24]

Imt200, that’s a good question. In my opinion.. it would be more your ammo temp. that will cause you to see those stress signs if any. the ambient air temp. affects the flight of the bullet which is resistance “air density” on your bullet as it is traveling through the air.

[@fhsauce]

Instead of writing on the case itself, I just mark off a letter on the case head with a sharpie and write that on my reloading data. Example, H = 42.5 O = 43.0 R = 43.5 N = 44. That would be the H in Hornady, etc. I think this is faster than writing out the actual numbers.

[@8541tactical]

See if there is anything you can do to improve your load development process.

[@RangerCaptain11A]

just make a series of targets on a strip of paper, one target per charge. then connect the shot holes and look for the place where the lines are flat, not sloped.

[@sorenfranson3323]

Very interesting video, but how would you divide the charges for a .223? At 6:22 you say that we will load the first cartridge at 10% below the max load. I'm currently loading up some Sierra MK 69 gr with Norma N201. Norma says minimum load is 23 gr and max is 24 gr. 10% below 24 gr is 21.6 gr, 8% below 24 gr is 22.08, and 6% below 24 gr is 22.56% - all below the stated minimum load. Any thoughts?

[@Ensign_Cthulhu]

Gave this a go on the weekend and it did not work well, but I suspect most of the problems related to "the nut behind the trigger" (i.e. me! - pulled a lot of shots for various reasons), and many lessons were learned (the hard way!!) in how NOT to conduct this test. However, I did notice a few tight two-shot clusters appearing (with three shots fired at each charge weight), which while it doesn't say much, was heartening in view of them not being shot close together in time (i.e. they seem to be genuinely grouping together, not just because I caught the same lull in the wind for both shots) & indicates the _possibility_ of fairly tight groups. Came back and watched this vid again, and can see a whole lot of places I might have done the whole thing better (the nut behind the trigger needs tightening up!!). We shall see what happens next time. One thing I did note - if those clusters are real and the best of what I observed turns out to be true, and not just a fluke, I have a sub-MOA SMLE. That can't be right. Surely that can't be right.

[@Ensign_Cthulhu]

***** Yeah, like I said - a lot had to do with the fact that this was the first time I'd tried it, so I screwed it up horribly. I went back and made detailed notes to myself about exactly HOW I'd screwed up, and the next time round will almost certainly work a whole lot better. I suspect the best thing to do may be to shoot a modified ladder at short range, using that to establish safe maximum charge and maximum vertical dispersion, then I can run the OCW string on the next range visit and have one less variable (i.e. charge weight safety) to concentrate on.

[@Tsorenson24]

Like John mentioned in the video, as you shoot your rifle, the barrel and chamber heat up.. that can affect your ammo temp. which I think your accounting for by shooting low to max and then reversing it. your barrel is being heated to a relative temp. as your running you load development. So, you should be good to go with the the methods John just showed us in any ambient air temp. range, as far as stress signs and maximum charge is concerned.. again that’s my opinion.

[@jeffgilkison6170]

the groups are shot in round robin format one charge weight at a time to get an avg barrel condition across all shots

[@earlcox5896]

Well done brother

[@jamespierce8786]

Thanks for the great info and the hard work that went into it.

[@Ensign_Cthulhu]

I suspect that's why he's choosing Varget - it's temperature-insensitive. Also, IIRC up-&-down barrel vibrations at certain "nodes" CAN cancel out velocity variations within limits by the way they alter the angle of bullet departure. The British noticed this with the Lee-Enfield; at certain ranges with ball ammo, group size in MOA would perversely tighten, which made some long-range target shooters switch to SMLEs at the "sweet" distances then back to something else at other ranges when allowed.

[@flipping_for_funds]

I like that idea. I may have to try that myself. Kind of a combination of the OCW and Ladder test. Your target would have to be perfectly level though.

[@lmt200ish]

Never thought about the Varget. That would help, isn't Varget less sensitive but not insensitive? With the Varget and picking the middle of the node from this test you probably will get as accurate as one can be. Interesting, I will try and more info on the Lee-Enfield you were talking about.

[@ThaiTanCorner]

I got tired of walking so o either color code or pre mark target to charge weight then shoot each strings accordingly

[@jeffgilkison6170]

Deanomag, unless you scrub the bore perfectly clean every few shots then you won't build a copper equilibrium and have consistent bore conditions. Idk about copper removing powder but you don't want to scrub all the copper out of your barrel every time you shoot or you will never have a consistent bore.

[@lmt200ish]

I am new to reloading and long distance but cannot find anybody talking about when you do load development at say 60 F and find a perfect load you lose that node/accuracy at any other temp. If the ambient temp. is 95 F then the velocity will have changed at least 60 to 70 fps and that node will have been lost, and may start seeing pressure signs. I know there is only so much a person can try to control but does this make the test somewhat "inaccurate".

[@nick.laufenberg]

This was extremely helpful. Thanks John!

[@Tsorenson24]

So on a hotter day your air is less dense and the bullet will be able to move faster with less resistance. But, If your ammo Temp goes up, Do to the ammo box sitting on the dash board of your truck in the sun all day. Then, yes your burn rate will rapidly increase, and I assume.. you might see stress signs.. and yes your MV will be higher.

[@ufdiver06]

Great Video, Thanks for all the insight. What is a good value chronograph? Do you have any setup tips for ensuring the results are accurate? Thanks and keep up the great work!

[@Rhyno430]

Thanks John, gave me some ideas.

[@RealitySurvival]

Good Stuff John! Thanks. jj

[@drmaudio]

If you have access to a 300 yard range (which I do) would you consider a ladder test superior to or easier than this method?

[@randoman75]

If all you're looking for is velocity, couldn't you just use a chrony for a ladder test and eliminate the difficulty of picking out which rounds went where on a 300 yard target?

[@anthonymurphy9513]

What a great a rifle you have there, i waiting on my rock river lar 8. I have a colt ar, ithinking of putting a match trigger, would stick with a colt brand match trigger or go with rock river, timming or one of great trigger that are on the market?

[@Soldier4USA2005]

When pulling apart "over charged" cartridges, as prescribed in the video, what do we do with the unspent primed brass??? Do we fire it??? Is there a depriming tool for unspent primers??? How would I take apart a cartridge without damaging the brass, if possible, for later use???

[@kihara4244]

Triangulating......I would have gone for 45.5 as the center point for the 2 loads around it is identical and start playing with seating depth for group size

[@Deanomag]

Great info! I will be using CFE223 for my latest .308 168gr Sierra Matchking, Winchester brass, Sellier-Bellot primer load workup. In preparation for the CFE223, which boasts a 'copper fouling eraser' property, I did a complete bore scrub with Copper solvent. Bore is almost pristine. How many fouling shots do you recommend before you start seeing a relatively even bore condition and you can trust the groups you are seeing? Thanks!

[@symgamer4382]

Awesome job, gave me a lot to think about

[@minervius]

Interesting barreltime approach. makes sense to my ears and I am going to utilise it. but why not make 5 shot groups 3shot gorups may lie to you with all the barrel-temperature and shooter-error possibilities. 5 shot groups do forgive a flyer

[@Ensign_Cthulhu]

Question: how do you answer the claim of "A 3-shot group is too small! You have to have at least 5 (or whatever their pet figure is)"? I'd argue from the aspiring big-game hunter's perspective that I'm not going to engage any one target with > 3 shots; beyond that, it's either already dead or got away. I don't know what your tactical match rules are, but I can imagine time constraints beyond which any target not successfully struck must be forfeited & you're forced to move on to the next.

[@jeffgilkison6170]

so when you find the ocw using this test or the ladder test then try to find the optimal OAL won't that change your optimal charge weight since the internal volume of the case is change and the resulting explosion has a different pressure and causes the barrel to vibrate at a different frequency/amplitude?

[@Munky332]

Here's a question, not really specifically for the charge weight, but when you started talking about the chamber i just remembered something. so, we all know 5.56 and 223 are close, but not necessarily the same thing, and i'm in the market for a bolt action "fundamentals training" 223 rifle for cheap practice, vs burning up my 260 ammo. which chamber is better, and why? IIRC the 223 chamber, while not recommended pressure wise to fire 5.56, has a "tighter" chamber, does it not? ie it has less "jump" from the bullet to the lands? i'm considering the Mossberg MVP predator. i believe this technically has the 5.56 spec chamber. my only complaint with this based on the spec sheet is the 1:9 twist. i'd really much rather have a 1:7 or at least a 1:8 twist, because its a bolt gun, so i'd obviously be running the heavier stuff through it, not the 52gr plinker stuff. well, i probably will also run that through it, and I can see why they did go this route, but still. 1:8 would have been a better choice IMO. my other choice was to get a Savage Axis II XP, but at around 350-400$, and i'd want to throw it in a boyds stock anyways for another 150$... it'd be easier to just get the MVP from the get go and be able to use my USGI mags thoughts? comments? recommendations?

[@kevanjdm]

Best to test this in semi auto or gas cut off? Would one vs the other give you different accuracy nodes?

[@DonziGT230]

Targets 5 & 8 look really good to me, can you explain why you didn't have much love for those? I'm prepping to do some OCWs and trying to really figure it out as much as possible before going to the range.

[@therabbit50]

Thanks for sharing that very informative insight.

[@jstephlaw7252]

What are your recomendations for rounds that take a lot of powder (i.e. 300 WM/338LM)? The velocity and energy I am looking for starts 6.6 grains below the max load according to the Hornady manual. This would turn into nearly 30 groups. The cost of this would be more than I am willing/able to spend. Would you recommend increasing the step up from 2/10ths of a grain to 4/10 or 5/10 or should I focus on a 2 or 2.5 grain window?

[@Jackomason]

yes velocity doesn't matter at 100 yards but doesn't it start to screw with you if your loads are inconsistent out at 1000?

[@alanlisitano5899]

Question, when getting the volume of water in a case do you use regular tap water or distilled, deionized? When I worked in a material testing lab whenever we did water weight we always used deionized water as the minerals in tap water would change the actual weight. Thanks for the excellent reviews you do each week.

[@motorgearhead]

Your methodology for selecting your accuracy nodes based on if a group center is high or low compared to Point of AIM doesn’t make much sense to me... seems you would want to use which ever node groups the tightest with the highest velocity. If a group is high or low or left or right it can be adjusted using your optic. Your load just has to be repeatable which is demonstrated by having multiple bullet holes close to each other. So, as long as you have a velocity that will deliver a projectile to a given distance and that load is consistent (bullets group tightly) you have a potential load that will meet your needs. Now what I do is test a couple 10ths above or below that charge weigh to see if you are in the middle of the node. Like so many things in shooting, different strokes for different folks but bottom line if you have the BC, velocity and consistency, you have a load capable of meeting your goal.

[@briang1891]

Can you talk about complete vs. incomplete powder burn. I am loading 308 with R-17 because it's all I can get. The rounds group well but with huge flame out of 20" barrel. Does this mean that I am loading too much and the extra powder is just wasted? Is there a point, within safe parameters, when more is inefficient? Can a barrel only burn so much?

[@stevelovesterri]

Question about OBT- If I have a rifle that I shoot 90% of the time suppressed, would that change the barrel length I pick? I have a TB Can that is direct threaded onto a flash hider, so I would expect that to influence the shock wave, but not the same as a one piece barrel with the same overall length of my barrel+Can.

[@8541tactical]

+Steve Evans The can should not touch the bullet, so the length it adds is not factored into barrel length for OBT.

[@msmith6401]

So why did you not like the 45.4-45.6 node, I would have thought that 45.5 would be a good node?

[@FistOfOak]

Good job! I have all the usual issues with my optical chronograph - shots not registred, sensitivuty to light conditions etc. Now I have tried a sonic cronograph (that is crazy expensive). It´s called Superchrono, take a look at steinertsensing "dot com". So far it has not missed a single shot. The manufacturer claims it to be accurate, I have not compared it side by side to my old chrono, so I really can´t tell. Do you have any experience of it? Maybe something to test?

[@djarecke]

What chronograph have you found the best results with? Any recommendations for the M40A-5 with Varget and the 175 SMK? I've ordered a GAP and I'd imagine that this load has been tweaked to the nth degree. Thanks very much!

[@matthewforadori9487]

After doing the OCW test myself and then hearing a more experienced reloader explain it further helped me pick up on some smaller thing I was overlooking. Thanks! On another note, do you use anything like the "On Target" program to help get a more accurate measurements (adjust to center)?

[@Tsorenson24]

Yep, the round in the chamber, will heat up to match that temperature of the chamber very quickly. That is why, when you see guys on here shooting very long distances.. they will wait until they are ready and have everything doped, check the ammo temp, then load that round into the chamber and fire it as soon as possible. but, if your just loading it one round at a time and waiting a few minutes between shots.. you should still be sending rounds down the barrel at roughly the same temperature.

[@Tsorenson24]

I replied to your question, but in the video comment box on accident. I Hope this helps you.

[@TheWheels1965]

HI, I live in Australia, and ammo is starting to get hard to get now, is it still bad in the US for primers, bullets, powder and cases, .22lr is getting very hard to find now. cheers

[@wjennin1]

This is great stuff!

[@zekeanthony]

Wow, I like it man, excellent stuff, but there's no art in there.

[@Tsorenson24]

Thats just my thoughts on it tho.. I could have the wrong thinking there.

[@8541tactical]

Geissele all the way.

[@red1tpm]

Excellent

[@jeffgilkison6170]

Deanomag,

[@sniperworx]

John, did you have a eye booger the size of a walnut or what? Lol

[@swtnix]

your finger....lol

[@godofm3tal1]

Those are at 100? Jesus Christ man.. get a new barrel