Slower powder for AR10 loads?

[frame12]

This comes from an inadequate primers in the cold (if there's just not enough spark to light it off consistently) or inadequate primer strike; either a lightened hammer spring in a tuned trigger, or maybe too much or wrong lube in the firing pin channel in cold weather, etc. A similar thing can be seen in magnum revolver cartridges when the hammer spring is lightened too much; velocity variations go way up because ignition is inconsistent.

I've had 2 people tell me they had the same "SRP with ball powder" issue. Just to clarify, they were using bolt guns.

All of the SRP's I tested with StaBall Match had some level of delay firing. Could be the cold. Some primers went off but failed to ignite the powder. Color of the powder was slightly brown compared to fresh.
I thought about FP issues. I'm using a G2S Brownell's enhanced 2 stage trigger, 1.25lb (didn't verify).

I may have missed it, but don't think you said - do you fully understand tuning the gas system, and have you tuned it for the max loads you're using? Doesn't count if you tuned it for some other load, or just "have an AGB", especially if you're using Superformance - you've gotta tune that gas system specifically for Superformance if you're using it as intended for high velocity loads.

Maybe I don't understand. I had a dual ejector BCG that was beating up my brass. I thought my gas was too high. I turned it down slightly. Haven't played with it since.
I have a brass catcher/deflector with about 3" of clearance. With the normal BCG, brass will occasionally not clear completely from the rifle.
Not a problem yet as I'm only single feeding per the match rules.

I don't have any confidence in my velocity numbers right now. But the 490 yard targeting system has me ~1850 w/StaBall & SMK140's, ~1935 w/H4350 & 130 Hybrids and ~2150 w/ Superformance & 142SMKs.
Apparently according to the match director, those numbers are also suspect.

Superformance powder seems to work fine.

I don't believe I'm running light loads. In fact I'm convinced I've been over pressure for almost everything I've shot.
Because when run the same load with LRP their pockets are getting loose after 3 firings and rims are deformed enough that they don't fit in the shell holder and spin freely.

 

[frame12]

IME when people talk about ARs having to run milder loads, most of the time its because they didn't tune the gas system very well, if at all. I'll also point out that tuning is a lot more important than what gas system length you have, but unfortunately most people just focus on that length instead of setting up the rifle right.

That's probably true.
It still seems like, from the bulk of the responses, that everyone believes I should be able to get 62k psi out of a firearm that was designed to run at 52k psi, if I just tweak it a bit.

 

[FredHammer]

That's probably true.
It still seems like, from the bulk of the responses, that everyone believes I should be able to get 62k psi out of a firearm that was designed to run at 52k psi, if I just tweak it a bit.

If you want to really keep within the pressure specs...develop the loads as a single shot with the gas block shut off. (With the faster burn rate powders as mentioned) Analyze the primer pockets diameter growth. Settle on the fastest load that doesn't show more than .0005 growth in the pocket. Then confirm that load will operate the gas system on at least one successful setting. I think this method would really keep you out of over pressure conditions.

Ejector smears are a different aspect, and pertains to the BCG dwell time and speed. Commonly mixed in with pressure signs, but really a matter of managing the buffer spring and buffer weight for optimization.

Gas guns are some intriguing shit! lol

 

[Cascade Hemi]

Small rifle primers are known to have ignition problems in cold climates with larger volumes of powder. It is worse with ball powder but not exclusive to it. The more air volume in the case they greater the chance you experience inconsistent ignition.

 

[Yondering]

Maybe I don't understand. I had a dual ejector BCG that was beating up my brass. I thought my gas was too high. I turned it down slightly. Haven't played with it since.
I have a brass catcher/deflector with about 3" of clearance. With the normal BCG, brass will occasionally not clear completely from the rifle.
Not a problem yet as I'm only single feeding per the match rules.

I don't have any confidence in my velocity numbers right now. But the 490 yard targeting system has me ~1850 w/StaBall & SMK140's, ~1935 w/H4350 & 130 Hybrids and ~2150 w/ Superformance & 142SMKs.
Apparently according to the match director, those numbers are also suspect.

Superformance powder seems to work fine.

I don't believe I'm running light loads. In fact I'm convinced I've been over pressure for almost everything I've shot.
Because when run the same load with LRP their pockets are getting loose after 3 firings and rims are deformed enough that they don't fit in the shell holder and spin freely.

A few things to unpack here, so I'll start from the top:

- Dual or single ejector bolt is (for the most part) independent of gas tuning. For people not single feeding, and expecting good semi auto reliability, the general rule of thumb is to tune with one round at a time and an empty mag inserted, and adjust gas restriction so that the BCG just barely locks back, then add a little more so it'll lock back 10 times in a row. That's generally a good setting for reliability; if you do a lot of mag dumps, run really dirty, or use full auto, a little more gas can help, but don't want to go too far.

In your case though, it sounds like you don't really need semi-auto function, so I recommend tuning so that the BCG locks back, and then restrict gas a little bit more so that you still get reliable extraction (it sucks having to do it by hand every time, although you can do that if you want) but you can get away with a bit less gas than full semi-auto function normally requires. This is better for brass life AND gun parts life, if it works for your application. Unlocking will be delayed a little bit more than normal semi-auto function.

- Superformance is a good powder for top velocities in the 6.5 Creed, although personally I had inconsistent accuracy results. One day it's shoot little bug hole groups, just really hammering, then I'd come back another day in different weather conditions and it'd be all over the place. It's pretty temp sensitive, and I came to realize the accuracy nodes I was finding with it were so narrow that some weather conditions were moving the load outside the node.
More importantly for your issue though, Superformance creates a LOT of gas compared to other Creed favorites like H4350 or RL16. This means that you really do have to tune the gas system for the Superformance load. Make sure to tune for the top end load you're using, not a milder load. You'll most likely find that once tuned that way, it won't cycle or extract fully with common H4350 loads.

- Now, did you say you're using Staball Match? Not Staball 6.5? I see Hodgdon does have load data for Staball Match for the Creed, but honestly I think it's a bit too fast of a burn rate, which is of course reflected in the lower velocities they list. The problem with using a powder where the burn rate is a little too fast, is you can spike pressure really quickly while velocity still looks pretty low and mild. It's quite possible this accounts for your pierced primers.

- And if you're loosening primer pockets, then it's almost a sure thing that your loads are way too hot. I tend to run warmer loads than a lot of people, but have a personal metric for primer pockets to stay tight for at least 4 reloads. Primer pocket loosening generally indicates one of three things:
1 - the peak case pressure is too high
2 - the case shoulder was bumped back too far, causing excessive headspace (this can look exactly like high pressure)
3 - the brass case head is too soft

While I've encountered all 3 of those, the third one isn't very common, and is unlikely to be your issue. #2 certainly could be; you haven't commented about how you're sizing brass and bumping shoulders, and that condition could explain the pierced primers too. Or, maybe it's #1 and your loads are simply too high pressure for your rifle.

If you know for sure that you've got #2 taken care of (this has nothing to do with a headspace gauge, and if you think it does we should discuss that too), then the issue is most likely #1. I'd start by double checking shoulder bump, and if that's correct at around .003"-.004" or less, then you should immediately drop your powder charges by a full grain or more, because that'd be telling us that your loads are running well over 62 Ksi, more likely in the 70+ Ksi range to loosen primer pockets.

One final thing - if you've had very many pierced primers, you should pull the firing pin and examine the tip. It could be eroded with some sharp edges now, which will just make it continue to pierce primers. If that's the case it'll need to be replaced; that tip needs to be smooth and round.

That's probably true.
It still seems like, from the bulk of the responses, that everyone believes I should be able to get 62k psi out of a firearm that was designed to run at 52k psi, if I just tweak it a bit.

Speaking for myself, I know for a fact that you can run pressures that high in these guns, reliably and with good accuracy. Even my lightweight BCG/buffer 308 setup is reliable with hot loads, because it's tuned to work that way. Tuning is a huge part of this, and the most commonly misunderstood & skipped part of setting up an AR, whether small blocks or big blocks. A lot of people struggle with large frame AR function, but there's a lot that goes into it and if you skip or don't understand some parts, there will be a lot more problems than with a simple bolt action.

 

[frame12]

I don't think I've had any punctured primers with Superformance. Looking through my notes, probably half of them were CCI400's. I've had a couple loads that were LRP (Magtech and BR2s). I feel pretty confident those were too hot. No punctures with Fed AR Match SRP.

Shoulder bump.
I pop out the primers with a decapper, clean up the head if it's got burrs, use a comparitor and zero it out. Full length resize and screw in the die till I see the shoulder move. (Hornaday Custom Grade FL Die with the expander ball removed.) It goes from 0 to .007 just by breathing on it. Not even a degree of spin on the die.
All in all its a very difficult, 'sloppy', process to control. Even getting base line, pre-resizing measurements seem like +/- .002 just by spinning the case.
I have an RCBS case holder and a Hornady. The Hornady holder is thicker and seems to touch the base of the die right when the shoulder is making contact. That's helped with consistency.
Generally I'm usually .006 when I finally stop adjusting. I figure .006 is better than 0. IDK, I could try biasing toward zero and see if I get feeding issues.

Pretty much every time I test powders StaBall match gives me the smallest groups. It's a touch slower than Varget.
I didn't buy the first lb, but I bought 2 more since my loads seem to want to group tighter with it.
Haven't had any better luck with H4350, Varget, Superformance or StaBall 6.5.... Which is why I was thinking n160/165 or 4831sc: Stick. Single Base, Slower. I could go with n150 instead, since maybe my gun likes the faster powder?

Thanks for the long replies. I appreciate everyone's time.

 

[Yondering]

I don't think I've had any punctured primers with Superformance. Looking through my notes, probably half of them were CCI400's. I've had a couple loads that were LRP (Magtech and BR2s). I feel pretty confident those were too hot. No punctures with Fed AR Match SRP.

Shoulder bump.
I pop out the primers with a decapper, clean up the head if it's got burrs, use a comparitor and zero it out. Full length resize and screw in the die till I see the shoulder move. (Hornaday Custom Grade FL Die with the expander ball removed.) It goes from 0 to .007 just by breathing on it. Not even a degree of spin on the die.
All in all its a very difficult, 'sloppy', process to control. Even getting base line, pre-resizing measurements seem like +/- .002 just by spinning the case.
I have an RCBS case holder and a Hornady. The Hornady holder is thicker and seems to touch the base of the die right when the shoulder is making contact. That's helped with consistency.
Generally I'm usually .006 when I finally stop adjusting. I figure .006 is better than 0. IDK, I could try biasing toward zero and see if I get feeding issues.

Pretty much every time I test powders StaBall match gives me the smallest groups. It's a touch slower than Varget.
I didn't buy the first lb, but I bought 2 more since my loads seem to want to group tighter with it.
Haven't had any better luck with H4350, Varget, Superformance or StaBall 6.5.... Which is why I was thinking n160/165 or 4831sc: Stick. Single Base, Slower. I could go with n150 instead, since maybe my gun likes the faster powder?

Thanks for the long replies. I appreciate everyone's time.

OK, a couple more thoughts then, with that info in mind:

- Puncturing primers with Staball Match but not Superformance leads me to believe my initial guess is right, that you're running much higher pressure with that fast burning Match powder than you realize. You'll need to back that down significantly to be safe. Match is in the right burning range for 5.56 and 308, but the Creed needs a slower range of powder. That's why H4350 and RL16 are so popular for the Creed, but not for 5.56 and 308.

- Related to that, you're having all kinds of issues while trying to use different powders than the people who are having success with the Creedmoor. That should be a sign to take a step back to the basics to figure out what works before trying to forge your own path doing things "your way". If you have H4350, it'd be wise to go back to that for a bit and figure out what the rifle likes, and tune the gas system to match it. If you can't get a 140-142gr match bullet and H4350 to shoot well, the problem is the shooter*, the rifle, or the load prep, in that order. That's a pretty solid tried and true combination known to work well, so you might as well start over there to eliminate one of the potential problem areas. Don't forget to switch to a magnum or military primer too, which should eliminate the primer piercing issues unless your firing pin is already eroded.

*A common shooter issue with large frame ARs is follow through; if you're used to bolt action rifles this is one area where shooting the large frame AR is different, because there is so much reciprocating mass in that BCG/buffer along with the slower lock time of AR triggers. If that's an issue, work on a solid tight connection between the buttstock and your shoulder and adjust body position as needed to keep the reticle on target (or very close to it) throughout recoil. That's a lot easier to accomplish with a bolt action or single shot where parts don't move around during recoil, but it does make a difference on target and is worth learning. I say this just assuming you may not know since you came here for help, but if you already know all this just disregard and recognize I don't know anything about your shooting ability with this rifle platform.

- On shoulder bump: something sounds iffy from your description. For starters, make sure the fired cases you're measuring don't have ejector hole swipes and imprints; if they do you need to back off the load a little (or restrict the gas to eliminate swipes) and try again. If you're seeing .002" variation from spinning the case, and it's not from ejector hole imprints (which it easily can be), then you probably either have a chamber with a crooked shoulder, or something is wrong with your measurement technique.

I'd guess the problem is those ejector imprints though, since you're clearly running loads way too hot. You should not be seeing .006" change in bump from just a tiny adjustment of the die (the adjustments are small, but not that small); I'd bet you've got the case head rotated differently for some measurements, so one might have an ejector imprint against the caliper jaw, and the next one doesn't, etc.

.006" shoulder bump isn't terrible, and is better than a lot of factory ammo, but it's not ideal either just because it works the brass more than necessary. It's not enough to cause false pressure signs or puncture primers though; I'd expect something more in the range of .020"+ if that were the culprit. Short answer is that's something to improve, but not causing the issues you're seeing - I'm convinced now your issues stem from a combination of overpressure loads and a poorly tuned gas system.

(Side note - try measuring the shoulder position of various factory rounds compared to your rifle sometime, you might be really surprised to see some .015"-.020" shorter than your fired brass. It's eye opening to compare ammo like that to the much smaller window of shoulder dimensions indicated by go/no-go/field headspace gauges... Fresh brass can usually get away with that once, but you don't want to keep doing that for multiple reloads.)

Once you get those imprints eliminated, these SAC lock rings can help with your shoulder bump adjustments. I shared this pic in another thread yesterday too, but here it is again below. Those marks are .002" increments for shoulder bump, so you should be able to dial it in pretty easily. (3 marks on that lock ring will give you .006" change.) Just make a reference mark on the die that matches one of the lock ring marks, and adjust from there as needed.

 

[Yondering]

Also I forgot to mention earlier - when tuning your rifle's gas system, remove the shell catcher or deflector. Keep it simple and deal with one thing at a time. If you get the gas tuned right for your load, then add the shell catcher back and find extraction issues, then you'll know the shell catcher is causing a problem like maybe bouncing cases back into the ejection port, etc.

 

[Shoots 700's]

He’s not going to switch. He doesn’t listen

 

[232593]

In my opinion you are trying too many components outside the regular 6.5 load window. If you have 4350, LRP brass and primers try the typical 40-41gr load. Maybe start lighter since its an AR10.
Staball match is faster than staball. I don't see many here try staball match in 6.5Cr. mix that in with SRP brass and I can see why you are chasing your tail a bit.

get the known stuff to work first and then change one thing at a time from there.

I've had hangfires in 6BR, with Wolf SRM primers with ball powder so small rifle primers, even magnum, are finicky with ball powder.

Is that 40-41 grain load with 135s & 140s?

 

[frame12]

try measuring the shoulder position of various factory rounds compared to your rifle sometime

Base to Shoulder on my fired brass seems to be 1.566
My loaded rounds are 1.559-1.560
Hornady factory rounds are 1.55-1.558 147 ELDm's are the longest and American White tail the shortest. Also measured 143x's and 120m's.

It's not that H4350 doesn't shoot ok, it's just doesn't shoot any better and StaBall match seemed to want to shoot. However, I started this thread because now I'm not so sure.
I've shot over 100 rounds of H4350 and 130gn Hybrids in 2 matches and it shot about as good as the SMKs with Superformance or StaBall match.

*A common shooter issue with large frame ARs is follow through; if you're used to bolt action rifles this is one area where shooting the large frame AR is different, because there is so much reciprocating mass in that BCG/buffer along with the slower lock time of AR triggers. If that's an issue, work on a solid tight connection between the buttstock and your shoulder and adjust body position as needed to keep the reticle on target (or very close to it) throughout recoil. That's a lot easier to accomplish with a bolt action or single shot where parts don't move around during recoil, but it does make a difference on target and is worth learning. I say this just assuming you may not know since you came here for help, but if you already know all this just disregard and recognize I don't know anything about your shooting ability with this rifle platform.

I have no experience shooting bolt guns, really. Was going to get one and then my state banned ar's and parts. In disbelief, I started trying to order barrels from various online stores. One by one they all canceled my orders. Except Midway. Midway only had 6.5 Odin Works barrels in stock at the time, so here I am.
Cheers to Midway, sticking it to the commies.

I am getting better at keeping the target in the scope throughout recoil AND keeping my eyes open. I am aware of the gas heat from the muzzle warping my vision now. The first few times it happened I thought the corner of the target was blowing up. I even inspected it after the relay and was surprised to find it securely stapled down still.

Also, I'm using a 4-16x scope. There's some inherent error there for sure, easily 1/4 moa.

All that being said, my 308 upper shoots 2x's larger groups than my 6.5 upper. The Odin barrel is a significant improvement.
Nearly everything so far has shot a mean diameter of 1 moa and and max diameter of 2.
Not sure if that meets accuracy expectations or not. It puts me about the same as other gas gun competitors I've encountered so far.

Once you get those imprints eliminated, these SAC lock rings can help with your shoulder bump adjustments. I shared this pic in another thread yesterday too, but here it is again below. Those marks are .002" increments for shoulder bump, so you should be able to dial it in pretty easily. (3 marks on that lock ring will give you .006" change.) Just make a reference mark on the die that matches one of the lock ring marks, and adjust from there as needed.

That's great! Looks like 10 degrees for .002 maybe?
I'll have to investigate my setup further. Really seems like I go from no contact to .01 bump in 1/2 of one of those increments.

Related to that, you're having all kinds of issues while trying to use different powders than the people who are having success with the Creedmoor. That should be a sign to take a step back to the basics to figure out what works before trying to forge your own path doing things "your way". If you have H4350, it'd be wise to go back to that for a bit and figure out what the rifle likes, and tune the gas system to match it. If you can't get a 140-142gr match bullet and H4350 to shoot well, the problem is the shooter*, the rifle, or the load prep, in that order. That's a pretty solid tried and true combination known to work well, so you might as well start over there to eliminate one of the potential problem areas. Don't forget to switch to a magnum or military primer too, which should eliminate the primer piercing issues unless your firing pin is already eroded.

I've spent a couple hundred rounds with H4350. I initially thought it would be best.
I'll go back to that next, or a similar Viht powder... maybe n150?

 

[frame12]

Once you get those imprints eliminated, these SAC lock rings can help with your shoulder bump adjustments

I had 10 cases that needed processed.
Cleaned up my FL resize die. Decaped the cases.
Lubed the cases, then measured them @ . 1.564 +/- .0005
Screwed my die in and got a bump of 1.5605 on the first one. Marked out where I thought the SAC hash mark would be and ran another case.
1.562
seems like it's working correctly after all!
then I had make adjustments while tightening the die ring etc. Pretty consistent.

Thx again for that!

Once again, the SRP Alpha brass is unharmed after 7 loads. Rims are straight, pockets are tight, no bolt/ejector marks.
LRP cases (Lapua, Hornady, Winchester) are likely on or near their last firing after 3 loads. LRP are 'donor' cases from factory ammo, though. Maybe that makes a difference.

 

[mettee]

Going from, say, Hornady brass to peterson to norma and on to Alpha, quickly showed me that hornady brass is junk. It doesnt size consistently even after annealing in the amp. I was getting sizes that varied .010. This can happen with Federal brass as well, its not the best quality.

The Alpha and Norma and Peterson all sized consistently without adjusting my die.

Your brass is all inconsistent, to me, showing maybe why your results are. On the last page I recommended consistency, I think if you stick with a brass, powder, bullet, and primer, your results will change.

 

[Yondering]

Going from, say, Hornady brass to peterson to norma and on to Alpha, quickly showed me that hornady brass is junk. It doesnt size consistently even after annealing in the amp. I was getting sizes that varied .010. This can happen with Federal brass as well, its not the best quality.

Hmm. I'm not going to argue that Hornady brass is top quality; it isn't. But your description indicates a sizing or annealing issue. Properly set up, my Hornady 6.5 Creed brass shoulder bumps are all within .001" without doing anything special, and the same for every other cartridge where I'm using Hornady brass. If you're seeing 10x that variation, something's not right, and the brass itself isn't the cause. Maybe it's a lube issue or die setup issue, or maybe your AMP settings aren't doing as good a job as you think, but it's likely one of those three or a combination.

Some people way over-emphasize the differences in brass quality. While some brass tends to last longer than others because of harder case heads or more brass support, and some have more uniform case wall thicknesses, you shouldn't be seeing anything like you described with Hornady brass.

 

[Yondering]

Base to Shoulder on my fired brass seems to be 1.566

Do yourself a favor and zero the caliper on this measurement, as I described initially. Then all your subsequent measurements are actual shoulder bump with no math required. It'll save a lot of time and make the whole process easier.

It's not that H4350 doesn't shoot ok, it's just doesn't shoot any better and StaBall match seemed to want to shoot. However, I started this thread because now I'm not so sure.
I've shot over 100 rounds of H4350 and 130gn Hybrids in 2 matches and it shot about as good as the SMKs with Superformance or StaBall match.

H4350 will shoot more accurately over the long run than Superformance because of the temp stability. While your best Superformance groups might be great, that's not the measure of how well your rifle does overall, if it shoots poorly a different day. And with Superformance it will, while H4350 will generally stay pretty consistent year-round.

Staball Match is still the wrong burn rate and a poor choice of powder. I recommend dropping it from your Creedmoor use for that reason alone, especially in a gas gun. There is absolutely no way you're going to have that large frame AR running well with both a too-fast powder like Staball Match and a very gassy powder like Superformance without changing tuning between them. You'd do yourself a favor to set both aside and use either H4350 or RL16.

It shouldn't need to be pointed out again - you're having rifle issues, so eliminate some of the variables and use a load that's proven to work well by a lot of other successful shooters. Trying other powders to be unique and different isn't going to solve the tuning problems your rifle has.

Once again, the SRP Alpha brass is unharmed after 7 loads. Rims are straight, pockets are tight, no bolt/ejector marks.
LRP cases (Lapua, Hornady, Winchester) are likely on or near their last firing after 3 loads. LRP are 'donor' cases from factory ammo, though. Maybe that makes a difference.

That's still clearly an indication that your loads are way higher pressure than you think. LRP brass losing the primer pocket after 3 loads indicates you're in the 70Ksi range or higher - you really need to back that off to a safe level. SRP brass masks that issue, and while the brass case head can handle higher pressure, that high pressure is still there.

That is what happens when you use a powder that's too fast for the application, like Staball Match or Varget in the Creedmoor, and don't understand the pressure signs. Not a good situation.

 

[mettee]

Hmm. I'm not going to argue that Hornady brass is top quality; it isn't. But your description indicates a sizing or annealing issue. Properly set up, my Hornady 6.5 Creed brass shoulder bumps are all within .001" without doing anything special, and the same for every other cartridge where I'm using Hornady brass. If you're seeing 10x that variation, something's not right, and the brass itself isn't the cause. Maybe it's a lube issue or die setup issue, or maybe your AMP settings aren't doing as good a job as you think, but it's likely one of those three or a combination.

Some people way over-emphasize the differences in brass quality. While some brass tends to last longer than others because of harder case heads or more brass support, and some have more uniform case wall thicknesses, you shouldn't be seeing anything like you described with Hornady brass.

My die and set up, lube, sizing(measured), and annealing all produce the same results with the higher quality brass and select few pieces of hornday.

A large quantity of the Hornady brass sized okay, but also a large amount did not with variations in dimension. This is over 1200 pieces to give you an idea of the scale.

I believe the web/rim section of the Hornady brass has deformed on the pieces that show the sizing issue. It's likely the brass that suffers from this issue is because it was shot suppressed. I have not had this anomaly with the other brass as the web seems to retain shape.

I think I can safely rule out the amp annealer and the sizing based on results with the other brass I processed.

I kind of land on high pressure scenarios causing the brass to yield. This is a gas gun scenario. So if you only consider Hornady in bolt guns against this scenario you may be correct.

 

[frame12]

Trying other powders to be unique and different isn't going to solve the tuning problems your rifle has.

That's definitely not my goal. I simply looked through the load books/data and tried the powders I had on hand that had a recipe.
I chased the smallest shooting loads with further tests.