1st 223 Chrono test

[kmw1954]

Thursday I was able to perform my very first load chrono test shoots and was remarkably disappointed. I had 2 different bullets with 4 different powders with a total of 19 different loadings. All of loading I have shot numerous times before and getting the best results with those combinations.

The powders were Benchmark, BL-C2, TAC and Varget. When I started this test I had to change brass because I did not have any of the type I had previously been using ready to load. So instead I swapped out the brass for some LC 14 that I had set aside. It was all processed the same way at the same time into one uniform lot. Or so I thought.

The Chronograph being used is a Magneto Speed Sporter that my boss was gracious enough to loan me. So when I started the chrono testing I had 2 rounds left of a load that had become my standard, 62gr Hornady over 23.7gr TAC using either GFL or PMC brass.


I shot those two rounds first to heat up the barrel and still got a reading which was 2255 and 2258. I was impressed.

When I moved on to the testing the the first load shot was a 62gr Hornady over 23.6gr TAC with the LC brass... Numbers fell; 2731, 2730, 2740. Almost 120FPS Didn't really think anything of it. Next load in sequence same bullet over 23.7gr TAC. (which again has become my most stable load) Numbers; 2737, 2777, 2702.. last of this was TAC @ 23.8 and numbers; 2785, 2746, 2731...
Totally disappointed and discouraged.

As I continued all following loads proved out the same with the exception of one. Two loads with very good numbers and then one that was either extremely high or extremely low. The one nice load was Varget load with a 69gr RMR bullet that had an ES of 6...

Now I had only loaded 3 of each of these to shoot over the chrono so I didn't have any extra to shoot for groups. So again just absolutely discouraged.

My friend and mentor thinks this is a brass issue with the LC and suggest I load a few over again with the PMC brass that I have been using and retest.

 

[CoalCrackerAl]

I been loading .223 with 24 grains varget and 15 grains of 2400. With berry's .224 FMJ'S. Accuracy has been good with mixed H.S. I don't recall if i chronograph-ed them.

 

[kmw1954]

All of these have been loaded and shot repeatedly with excellent accuracy which is why I loaded them to chrono.

 

[CoalCrackerAl]

I wonder if humidity was messing with your results?

 

[kmw1954]

Don't see how. Readings are taken within inches of the barrel.

 

[CoalCrackerAl]

I put my chrono out about 15 feet. Im afraid the shock wave from the percussion would damage it.

 

[kmw1954]

I put my chrono out about 15 feet. Im afraid the shock wave from the percussion would damage it.

Different type of chronograph. https://magnetospeed.com/

 

[Charlie98]

I wish I had some data to compare... but I don't use any of those powders. TAC is on the wish list, however.

My standard load for the 62grn Hornady bullet is 23.5grn H335... it gives me 2750fps out of both my 16" RRA and 20" Colt. The accuracy is there in both of the rifles, so I don't see the need to push it to try to make it go faster. I would feel confident shooting that load out to 500yds.

If I might make a suggestion... and a comment.

You mention you have fired these loads previously and gotten good results.... are the results not satisfactory now just because they are not going as fast as you had hoped?

If I were you, I would pick one bullet and maybe 2 powders... maybe the 2 that gave you the best accuracy... and work just with those. If at the end of the workups you are not satisfied, drop the worst performer and pick up another powder. Setting down with 19 different loads is a recipe for disaster... I know, I've done it.

 

[kmw1954]

Thanks Charlie98, All of these are the results of load development. The TAC 23.7gr load with the 62gr Hornady bullet had become my standard, that was until I was given some Benchmark to try. So I was am am still satisfied with the TAC load and am still experimenting with the Benchmark. The 19 different loads was just curiosity from what I had already loaded. Have also already decided that the Varget and BL-C2 will not be used. Also maybe not the LC brass either.

The disappointment is in the wide ES and SD I received.. Trying to find a load to shoot in a local rifle league that shoots 100/200/300yds and I will be the rookie! Some of these guys are shooting Quarter size groups at 300yds,

 

[243winxb]

was 2255 and 2258

?

Numbers fell; 2731, 2730, 2740.

?

Is the 2255 and 2258 a misprint?

What is your barrel length? Has an effect on velocity.

 

[kmw1954]

?
?

Is the 2255 and 2258 a misprint?

What is your barrel length? Has an effect on velocity.

Yes mistyped
2855, 2858 are what it should have been, thank you! The disappointment isn't in the velocities but in the inconsistency. These numbers with this LC brass do not seem to match the consistent groups I was printing with the PMC or GFL brass.

 

[Hooda Thunkit]

And yet again it happens.

Someone is happy as a clam, shooting their pet load. Them they get a chrono and everything changes.

Now you're going to want to chase the single-digit spread.
You will burn pounds and pounds of powder comparing esoteric numbers that 90% of shooters don't understand.
You will have partial boxes of bullets left over from earlier experiments, the ones that didn't do exactly as hoped.
You will spend hours at the range, wondering why this or that didn't work out.

Welcome to the club..

 

[unwashed]

Iirc LC cases has one of the highest case capacity, so they may be loaded at less then the PMC % wise. This is why I always load my bottlenecks by CC instead of the load data. If your PMC are loaded to 94%, I'd bet the LC are at 91% which in turn lowers pressure, hence lower velocity.

 

[243winxb]

The disappointment is in the wide ES and SD I received..

My friend and mentor thinks this is a brass issue with the LC

Sure looks like a brass issue. Lapua brass is used by many. The long range shooters seem to have figured it out.

 

[lordpaxman]

The disappointment is in the wide ES and SD I received.. Trying to find a load to shoot in a local rifle league that shoots 100/200/300yds and I will be the rookie! Some of these guys are shooting Quarter size groups at 300yds

Chrono graphs will do that to you! At closer distances the ES/SD aren’t as important as groups on paper. You also have 3 shot populations, and drawing any statistical conclusions will have a low confidence. It might be tough to do but you may want to lower your expectations and save yourself some grief. There are many posts on this forum where the first chrono experience was an eye opener, myself included. I’d suggest you just continue to track the data on your “best result” loads over time. Good luck.

 

[Charlie98]

I was printing with the PMC or GFL brass.

I've always considered PMC 5.56mm brass pretty good stuff, even if the factory loads I shoot to get it are mediocre. I'm also a big fan of it in 7.62mm.

243 is correct, however... if you are looking to shoot with the big boys, you will need a specific lot of good, consistent brass for that purpose. I don't consider LC brass that consistent.

 

[JFrank]

Several great posts and to the point, your problem is consistency of combustion.
Could be a couple things..

Case volume = pressure variances = fps variances
Poorly weighed charges = fps variances
Mixed batch of primers = fps variances
Poor/ weak ignition = fps variances

 

[kmw1954]

Morning folks and what a nice group of comments to wake up to! Now to try and address some.

I am not surprised by the speeds as before this I had no idea what the speeds were and wasn't trying to guess, nor was I trying to obtain a certain speed. I was surprised by the sudden decrease in speed (so was my friend) by just changing brands of brass. Next, after shooting many of these loads more than just a few times and the results I was receiving I imagined they were much more consistent.

As to the only a three shot group , no there was no statistical conclusion other than what clearly appeared and that was each group had one shot that was significantly higher or lower than the other two and this repeated over the entire range of testing. Also each of these three load groups was loaded three times with a 0.01gr variance for comparison like the 23.6, 23.7, 23.8 TAC load. Which again in many cases the higher volume load shot slower than the lighter load. So yes I was also trying to verify a speed node but when comparing the 9 loads together the variation opened up even further.

So with the material being used, cheap FMJBT bullets and recycled range pickup brass, I was not looking nor expecting to find top shelf Match grade am munitions. But again just by past experience with these loads I was expecting them to be much more consistent. With this stuff and being shot out of my old Savage Model 10 I would have been ecstatic to find velocities in the 25FPS range or even a few that were wildly out of the range but to find that in every load. That tells me there is a problem that can be corrected.

Jim, I and my friend agreed that it is a combustion issue. Only we believe it is caused by the brass and is a neck tension issue and some case volume inconsistency. For these tests all brass was processed at the same time, the same way in one batch. All primers were also from the same box and Lot. Each powder charge was weighed and trickled up to load target.

So now my intention is to reload those TAC and Benchmark loads with both the PMC and GFL brass and shoot them again. I have tons of both, just not processed and ready to load.

 

[Charlie98]

Case volume is interesting. When I started loading cast, I had both a Savage 99 in .308, and a Marlin 336 in .30-30, both used the same bullets... a 173grn FP. I loaded up test loads in both cartridges with the same loading data... everything the same except, of course, the cartridge case. 28grn IMR3031 in the .30-30 case gave me 2000fps out of the Marlin, but only 1775fps out of the .308 Savage. It took 32grn IMR3031 in the .308 to hit 2000fps. I don't know why, but I was surprised at the differences in velocity between the two cartridges... I didn't really think it would have made THAT big of a difference over the chrono, and that it took 4grn more powder to achieve the same velocity with the same bullet in the bigger case. I had two other loads that showed the same thing, but in a lesser amount (with faster powders... IMRs 4227 and 4198.)

I'm not sure why I was surprised... I've known since I started loading .308/7.62mm for my M1a that there is a significant difference between commercial .308 brass, and military 7.62mm brass, enough that you can easily go over pressure just by switching from commercial to military with an established load.

I'll be curious... when you work up in PMC brass, again, if you will pick up that lost velocity.

 

[kmw1954]

Few more thoughts on this and the brass issue, Yesterday my friend sent me a whole email describing how to accurately measure the necks to establish neck tension and I will investigate this. He also suggested annealing the brass before processing and lastly suggested the use of the Redding dies with the bushings.

Have to say I agree and understand only at this point I am not sure I am ready for the step up to the better dies while still using cheap range brass. I think I need to work thru these issues first to gain a better understanding and then moving to better components like bullets and brass.

 

[Charlie98]

I think I need to work thru these issues first to gain a better understanding and then moving to better components like bullets and brass.

The biggest improvement you can make without any work... is a better bullet. The Hornady FMJ's you are using are probably the best generic FMJ you can shoot... so there is that, but spring for a box of 69grn SMK's or similar, and you might be surprised what that range brass can do.

 

[kmw1954]

I'll be curious... when you work up in PMC brass, again, if you will pick up that lost velocity.

That makes two of us! More so I will be interested to see if the consistency improves as well.

 

[kmw1954]

The biggest improvement you can make without any work... is a better bullet. The Hornady FMJ's you are using are probably the best generic FMJ you can shoot... so there is that, but spring for a box of 69grn SMK's or similar, and you might be surprised what that range brass can do.

I have also been shooting some 69gr RMR bullets and have been very pleased with them. Have also been watching for some SIERRA 62GR Matchkings.

 

[twarr1]

I'm surprised no one has mentioned weighing the cases. Sorting cases by weight is a proxy for volume. People say LC is 'thicker' but has more volume. Really? Those are mutually exclusive. The fact is, a lot of LC actually has less volume than commercial stuff, and it varies wildly.

 

[kmw1954]

I have read discussions on doing water volume testing but that seems to be much more work than I want to do as does sorting by weight..
I have a long way to go with my shooting prowess before I worry about being that precise!