Issue fixed. (Can delete)

[drmjf]

did you check?

No one has asked. Did you take the gas tube out and make sure the hole is pointed to the barrel. I had one today with the gas port pointed up.

[epilepticninja]

There's a pic of it. The brass fails to eject and load next round. So it jams after every shot.

Had the same exact issue, and it drove me nuts for two months before I figured it out. Want to know what I did?



































































...put a donut on the extractor spring. Never had a another jam again. The problem is the extractor spring in its stock configuration isn't strong enough to hold the casing so it gets loose inside the chamber. Thank me later.

[ott1]

Tried doing it with single load still same issue. With old BCG the brass stayed hook up to BCG. Now with JP Low mass BCG 1 in 15 round actually cycles.

Are you using a carbine buffer or rifle buffer?

[falbuff]

+1 check gas port size.

[Rock6.3]

What ammo are you using? Factory stuff, or light handloads?

If you manually operate the bolt (firmly) do the rounds eject?

If your gas block is adjustable I suspect the port needs to be opened up more to allow the bolt to fully cycle to the rear.




And my experience is that these uppers take quite a bit of break-in time, during that time they need lots of lubrication. (That was the experience from my last two LR308 builds)

[phrogg111]

Dumb founded looking for a true gunsmith/someone that really knows AR'S in Sacramento area. If replaced buffer, buffer spring, brand new JP BCG, JP barrel, new CMMG LPK. Colfax tacticle completed lower. And still failure to eject rounds. If tried 5 different mags. Replaced All the parts listed and now being told from Sacramento Black rifle it is lower or upper on how it's connecting. Yet they aren't sure. If that's what it needs ill buy it just want to make sure instead of buying more and more stuff.

Failures to eject?

The common problem I've seen is that the first 5-10 rounds will fail to eject. My friend's AR-10 would fire and the bolt carrier wouldn't even move. After using a screwdriver in the bolt carrier and a hammer on the screwdriver to get it out a few times, and after using his finger to cycle the bolt in and out of battery a bunch of times, the gun works fine.

I had the same problem on my bolt-action AR-15 build. After break in, it worked flawlessly.

[MIGUEL RUVALCABA]

No only the BCG is JP. Upper receiver is DPMS and barrel is also JP.

[KeeperOfColdSteel]

I do some work for Ammunition Supply Point Solano in Vacaville, but I'm located in sac. I can take a look at it if none of the above ^^^^ work out.

[twotacocombo]

^^^ good idea, to separate gas issue from extractor/ejector issue.

Also ensure you're not using a rifle-length spring in a carbine tube, which can impede travel of the BCG and cause FTE problems.

[baih777]

did you buy the barrel and bolt from JP together ?
have you tried "removing the firing pin" and cycling 10 rounds of ammo.

[MIGUEL RUVALCABA]

Tried doing it with single load still same issue. With old BCG the brass stayed hook up to BCG. Now with JP Low mass BCG 1 in 15 round actually cycles.

[twotacocombo]

Tried loading and firing a single round to see if the bolt locks back? Make sure you're not short stroking...

[ptoguy2002]

Heavier buffer weight?

[MIGUEL RUVALCABA]

Dpms

[ott1]

Whose buffer are you using?