JP Enterprises LRp-07 in 6.5 Creedmoor

[The Lawn Ranger]

What sizing dies are you using?

I am having chamberring issues using an RCBS small base die.

I run the rifle suppressed and it seems with the smallest build up
of crud in the chamber from back pressure and the issue happens.

I clean the chamber and it runs for about 10-15 rounds and the issue happens again.

No issue with loaded virgin Hornady brass. I was hoping for insight here before calling JP.

 

[The Lawn Ranger]

Disregard.

I am going to run the break on it as cleaning this thing every time I shoot it
Is a PITA.

I will continue on with RCBS s/b die and report if chamberring issues persist.

 

[Temp9]

How are you setting up your die? You should be bumping at least .002" for an autoloader. Possibly more, but I never do.

 

[The Lawn Ranger]

.002" shoulder bump.

 

[pinsandpitons]

The CM is a pretty straight case. (you prob know this) Is that what's causing the issue do you think? Could slowing down the cycling rate help? Adjustable gas block, heavier buffer? I don't know what you've tried.

When you say no issues with virgin brass, do you mean it'll chamber normally all day? Are there measurable differences between the virgin brass and RCBS sized brass? Maybe you just got a "big" die.

 

[The Lawn Ranger]

Yes, the rounds loaded on the new Hornady brass cycle fine.

The ones sized with the RCBS die get hung up over time when using a suppressor.

I went ahead and put the break back on today so the problem is hopefully mute now.

I still plan on calling JP to get their take.

 

[POSM]

Hey guys, I have a JP CM as well and have loaded both virgin Hornady brass and made my own from LC 09 headstamp. The latter is quite a PITA, but I finally got that process down so that it is reliable and good cycling brass even with my suppressor (Surefire). Both would occasionally jam a feed, but that was when I was loading to 2.815" (cramming it into my magazine). I resize first on a Redding full length bushing die (.289 bushing), then run it through the RCBS small base die in a second pass. Then trim it to about 1.910" on a Garaud trimmer which references off the shoulder. I turn necks when necessary. But the KEY to NOT HAVING ONE FAIL TO GO INTO BATTERY is to check them all with a WILSON CASE GAUGE. JP uses Wilson reamers. Occasionally, a brass will pop out of the dies with a bit of extra length. I can't explain why. But when it is proud (even a microscopic amount), that case might not feed. So it's probably headspace, not diameter, that is keeping your JP 6.5 CM from running suppressed. I do have a question for you: HOW DOES YOURS GROUP. MINE GROUPS LIKE SHIT. USUALLY ABOUT 1.5 TO 2 MOA. I've tried every possible combination of bullet, powder, charge, seating depth and brass. I've chrono'd hundreds of rounds, shot ladders, shot groups with .1 gr steps. Best group ever was 1.06 MOA and that was with my worst velocity distribution (so it was just luck). I'm sending it back to JP after the Mammoth Sniper match and see if they can figure it out. thanks.