Problem with 7.62 REPR16

[jdben92883]

Bought this from another CalGunner a few weeks ago and finally had a chance to take it out for a run and zero in the sights. Unfortunately, I never got that far. I had a 10/20 PMAG loaded with steel commie-ammo. First shot, bang. No 2nd shot. Bolt is locked closed solid. Some jerking, some pulling, and some muscle to the point where I'd be concerned if the bolt handle wasn't so robust. It finally pulls free and spent round is ejected.

Repeat the exact process for round #2.

Replace ammo with brass-cased Magtech M80 for try #3. Exact same thing.

Pull out PMAG and use a good quality steel mag with brass Magtech for try #4. Same results but with a whole bunch of smoke coming out of the mag well. Smoke lingered for many seconds. Spent cartridge looks oily/wet.

Put gun down and shoot another rifle. Before packing up, tried hand inserting a steel cased round without a mag. Exact same thing.

So I'm 100% failure and that bolt completely locks up. For what it's worth I put a snap-cap in at home and it dry-fired/ejected without a problem.

Any ideas here? Is my shell casing expanding to the point it's getting lodged in the chamber and if so what could be causing this?

[Moemoe1]

Send It to LWRC they have great customer service

[jdben92883]

Located what I assume is the heart of the issue. The gas regulator was on the "C" (closed) position. The previous owner mentioned hunting with it, so I assume he closed it up for some reason. I was really concerned that the bolt was able to be locked in place under so much pressure, but I guess there wasn't any pressure at all.

Does anyone happen to know why it's so difficult to manually cycle? I didn't go ape-crap on it and start banging it on the bench, but I did NOT tenderfoot it either. Someone with less strength wouldn't have been able to cycle it at all.

[CRTguns]

LWRC will tell you to go get stuffed. You cannot use steel case in a piston AR. They tend to try and unlock very early on... while pressure still in barrel. And steel is not elastic in the first place... it does not spring back away from chamber wall after firing like brass does.

LWRC gets brass cased non-comie block ammo.

Got it?

[Moemoe1]

I call BS on your comment ^ I have 2 lwrcs well had and one I have ran over 2K rounds of cheap wolf ammunition through my M6A2 and have never even had a FTF or FTE.

[kcstott]

The issue with steel cased ammo is the varnish coat. Not that it doesn't spring back from being fired, I call BS as well as steel will simply
not expand as much as brass will.

Do not shoot brass cased ammo in a rifle that has shot steel cased ammo with out a thorough cleaning of the chamber to remove any trace of the coating

[jdben92883]

I can appreciate the idea of lacquer fouling. Not sold on the anti-steel concept in pistons, though. The POF .308 that I recently sold had no issue with it. I still have a POF 415 which is impartial to steel .223.

After yesterday's initial experience with the LWRC, the rifle I used to take a break was a SCAR17 which gobbled steel up.

[PolishMike]

Yep, just open the gas system and it should run fine.

Pretty normal as far as being hard to cycle.

[FeuerFrei]

I can appreciate the idea of lacquer fouling. Not sold on the anti-steel concept in pistons, though. The POF .308 that I recently sold had no issue with it. I still have a POF 415 which is impartial to steel .223.

After yesterday's initial experience with the LWRC, the rifle I used to take a break was a SCAR17 which gobbled steel up.

I remember BARNAUL MACHINE-TOOL PLANT Brown Bear is one manufacturer of laquer coated ammo. Brown color.
Your rifle should be indifferent with ammo choice as far as coating goes.
Try some hotter ammo next time. The Magtech M80 load is not very hot either.
Try the PMags again. Run gas regulator wide open.
Load mag with one round only and see if it cycles and locks back.
I'm assuming you stripped and inspected/oiled/cleaned before you shot it.

[Plisk]

LWRC will tell you to go get stuffed. You cannot use steel case in a piston AR. They tend to try and unlock very early on... while pressure still in barrel. And steel is not elastic in the first place... it does not spring back away from chamber wall after firing like brass does.

LWRC gets brass cased non-comie block ammo.

Got it?

There is no way the weapon would unlock from battery prematurely due to it's ammunition.

Excessive backpressure from the casing, or gas escaping past the casing could not cause the bolt to unlock. Once the firing round passes the gas port in the bore, then pressure will flow into the gas block and begin the move the piston reward. By the time the piston is under pressure the round has left the barrel.

The OP discovered a very common issue with LWRC's multi-position gas block rifles. I personally have an M6A3 which has the same style 4-position gas regulator on the REPR series. It's common that the block is set on the wrong setting, typically C-Closed (Off). My rifle has had difficulty hand cycling certain types of ammunition.

As to the escaping gas coming from the magwell, that is an issue I would contact LWRC about. That is not normal during closed gas firing.

[jdben92883]

Thanks for the replies. Rifle was broken down and thoroughly cleaned/lubed before taking out. I'll be able to get out next week for another go at it. I have plenty Q3130 and Fed SMK to run through it. I usually go cheapest to most expensive as I get the sights dialed in, but I'll use some better stuff first on this guy.

[CRTguns]

I call BS on your comment ^ I have 2 lwrcs well had and one I have ran over 2K rounds of cheap wolf ammunition through my M6A2 and have never even had a FTF or FTE.

I did not say it would not work... said LWRC wont help if they kow youre feeding in combloc ammo.