Proof AR10 6.5 Creedmoor stuck case

[Billiam1211]

So I have an AR10 that I built with a Proof Research 24-inch 6.5 Creedmoor barrel. I have about 450 rounds down the barrel and accuracy has been stellar, however over the course of those 450 rounds I've had 3 instances of a case getting stuck in the chamber. Accuracy has been awesome, with this barrel my AR10 can hang with my bolt guns, but the reliability issue really kinda drags down the performance.

I'm currently using Hornady Brass that was initially fired in my bolt gun a few times, full-length sizing it, bumping the should back 0.005, and shooting a light/medium load.

Is this likely a situation where I just need new brass that is specifically for the AR10 or has anyone else experienced tight chambers on their Proof barrels?

 

[wvfarrier]

Is it possible there is a rough spot in the chamber?

 

[Flyingbullseye]

You ever trim your brass?

 

[SD Carpenter]

I fought with my ar10 with proof for over a year, customer service wouldn't respond etc. I got a JP and a craddock since then that run flawless. $450 pre-fit ar10 barrel is too good to be true sometimes.
It did shoot great though I won't take that away from them. But if a gas gun can't run reliably it's trash.

 

[Billiam1211]

I just checked the chamber and it looks pristine still.

Brass is regularly trimmed as well.

I already had a run in with Proof’s customer service.. this barrel wouldn’t cycle when I first got it. They told me to get rid of my JP LMOS and SCS I ended up opening up the gas port with a reamer. Barrel shot tiny groups after that. Since then I’ve had 3 stuck cases intermittently that I’ve had to tap out with a cleaning rod. Think I’m going to try some new brass or another small base die and see what happens

 

[msgriff]

I would also check out the bolt. specifically the extractor/extractor springs. Might help to post pics of the case bases, especially the ones which were stuck.

 

[B Man]

What about your extractor? How does it look like it is gripping the brass? I had this problem with federal brass but not Hornady in a 308 ar before, replaced the extractor with a JP enhanced and it ate everything I fed it after. Literally over 1000 rds and not one stuck case after.

 

[Billiam1211]

Well I think I figured it out, but I need to go to the range to confirm. As per usual, it's it comes down to me dropping the ball on reloading practices. I typically small base size on my gas guns, but this last time forgot to run them through the SB die. After measuring a few pieces of brass from the batch in question and comparing to a few pieces that were ran through the SB sizing die, there was about 2-3 thousandths difference. Guessing this is it.. Having twin 15-month olds at home, IF I can make it to the range which is rare these days, reloading is always last minute and rushed. I think I'll be making a physical reloading checklist so I can track what's been done to each batch that's been started.

 

[45-90]

Resize your brass with a smaller body die...I had similar trouble with one 308...but had 6 308 dies. So I resized the case with one, then another, then about the 4th die a lot more resistance, it happened to be a Hornady FL sizing die, which I didn't particularly like, (like their seating die) and it was a perfect fit for this 308 chamber, no stuck cartridges. They can still get stuck with a SB die, need the whole body smaller in my case... Also tried a Redding body die, for consistent shoulder bump, after resizing with the Hornady FL die.
Not all dies and chambers match up well...grab a few friends 6.5 Creedmoor dies and try them...don't forget to try a Hornaday FL die,...it worked for me. As slight spring back of brass after sizing and slight inconsistency of spring back leaves a taper in the cartridge and the taper in a snug chamber a perfect snug fit... that really grabs the cartridge case. Like a machine tool spindle taper...

 

[FALex]

@bigjake83 this dude's issue sound familiar? LOL!

@Billiam1211 you absolutely, 110%, need to get separate brass for your gas gun. I just ran into this issue with my newly-barreled JP. I have owned bolt guns and gas guns where I could run brass between both of them, but on this new CLE barrel, I cannot. The chamber is just too tight (not a bad thing) when compared to my bolt.

 

[bigjake83]

@bigjake83 this dude's issue sound familiar? LOL!

@Billiam1211 you absolutely, 110%, need to get separate brass for your gas gun. I just ran into this issue with my newly-barreled JP. I have owned bolt guns and gas guns where I could run brass between both of them, but on this new CLE barrel, I cannot. The chamber is just too tight (not a bad thing) when compared to my bolt.

Yeah as soon as I read his OP I knew what it was.

 

[Billiam1211]

new brass it is then I think I’m going to pick up a new FL and small base die and maybe try Starline 6.5 Creedmoor brass for the gas gun.

 

[Billiam1211]

Redding SB die and a bag of shiny new brass is in the mail

 

[mettee]

What does the brass look like after firing? How are the primers?

 

[Billiam1211]

Brass usually looks fine. Sometimes the necks get dinged up. HOWEVER stuck cases always look mangled, kinda makes sense tho

 

[mettee]

I'm thinking it's the sizing and/or it's a tight chamber?

I know you said you bumped them back 5 though, any idea what that is compared to a factory sized lapua case? Or any factory sized 6.5 creed case...

I have the sac comparator, and I measured fired cases, resized ones, and factory fresh ones. See where you land with your sizing.

 

[Billiam1211]

I'm thinking it's the sizing and/or it's a tight chamber?

I know you said you bumped them back 5 though, any idea what that is compared to a factory sized lapua case? Or any factory sized 6.5 creed case...

I have the sac comparator, and I measured fired cases, resized ones, and factory fresh ones. See where you land with your sizing.

I’m fairly certain I just need to small base size. On this batch I’m almost certain that I forgot to run it through the SB die because I was in a hurry and tired

 

[mettee]

I just measured a few different fired cases. SAC comparator.

Fired cases:

Hornady - 1.5420
Peterson - 1.5435 - I do not have any of these left factory sized.
Lapua - 1.5420

Factory sizing:

Hornady - 1.5390
Prime - 1.5400
Lapua - 1.5390

My sized case:

Mine - 1.5400 to 1.5390

Buddies pet load:

Buddies: 1.5300

I guess I'm trying to understand you bumping .005. Comparatively to what I'm measuring that's a lot. I'm shooting 260. Can you put your sized case in the chamber and have it tight, but still fall out?

 

[msgriff]

I just measured a few different fired cases. SAC comparator.

Fired cases:

Hornady - 1.5420
Peterson - 1.5435 - I do not have any of these left factory sized.
Lapua - 1.5420

Factory sizing:

Hornady - 1.5390
Prime - 1.5400
Lapua - 1.5390

My sized case:

Mine - 1.5400 to 1.5390

Buddies pet load:

Buddies: 1.5300

I guess I'm trying to understand you bumping .005. Comparatively to what I'm measuring that's a lot. I'm shooting 260. Can you put your sized case in the chamber and have it tight, but still fall out?

This image is for .308W, but small base dies form smaller body diameters.

 

[mettee]

I'm just more curious than anything. What causes what and how to solve issues.

 

[Billiam1211]

My fired cases are 1.532”
Sized cases are 1.527-528

I used to bump shoulders .002 but every once in a while in my bolt gun would have a hard bolt close so I just started bumping everything a couple thousandths more for reliability. Doesn’t factory ammo have a pretty huge shoulder bump? It’s the same idea

 

[Billiam1211]

Went to the range today and ran 50 rounds through the AR10 without a hitch. It was definitely the SB die. Turned the gas block down a few ticks and she ran smooth.