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10/7/2016 7:49:16 PM EDT
LMT MWSE 16" barrel with an Omega suppressor. Been running the ZQI ammo for plinking and some Federal for more precision.
I ran approx 500 rounds through this rifle suppressed with minimal issues. A few issues of the bolt not going into battery. Usually because it was dirty.




The last 2 times shooting after a few rounds a case gets stuck in the chamber. 1st time it happened the extractor took a chunk of the rim off the case. I had to remove the extractor from the bolt to get a tiny piece of brass out of it.

I did a good clean of the rifle.

2nd time on the 41st round a case got stuck again. Had to use a cleaning rod to get it out.




It seems the case is expanding in the chamber. I put that case back in by hand and it goes it pretty snug and will not fall out on its own. Put an unfired round in and it falls out on its own.




Measuring the stuck case (in inches) I get .4715 near the rim (primer end) and .4580 just below the neck.

Measuring an unfired round I get .4655 and .4545.




It's obviously over gassed with the suppressor but why would this start happening after 500ish rounds?
10/7/2016 8:29:51 PM EDT
[#1]


Quoted:



LMT MWSE 16" barrel with an Omega suppressor. Been running the ZQI ammo for plinking and some Federal for more precision.I ran approx 500 rounds through this rifle suppressed with minimal issues. A few issues of the bolt not going into battery. Usually because it was dirty.
The last 2 times shooting after a few rounds a case gets stuck in the chamber. 1st time it happened the extractor took a chunk of the rim off the case. I had to remove the extractor from the bolt to get a tiny piece of brass out of it.


I did a good clean of the rifle.


2nd time on the 41st round a case got stuck again. Had to use a cleaning rod to get it out.
It seems the case is expanding in the chamber. I put that case back in by hand and it goes it pretty snug and will not fall out on its own. Put an unfired round in and it falls out on its own.
Measuring the stuck case (in inches) I get .4715 near the rim (primer end) and .4580 just below the neck.


Measuring an unfired round I get .4655 and .4545.
It's obviously over gassed with the suppressor but why would this start happening after 500ish rounds?


View Quote



Just had VERY similar problem with my 18 inch JP Barrelled Mega Carbine.  My issue started at 500 round and the extractor started slipping off of the rim despite the gun being clean or dirty.   I am running all top shelf parts, heavy assed buffer and spring, etc.  The slip over of the extractor ended up crushing the extractor spring which to me meant my extractor spring was dying early and/or I had a LOT of bolt carrier velocity.  I ordered some new extractor springs from JP and turned the gas system off and started over.  Problem is gone and I noticed that I ended up setting the gas two clicks UNDER what it took to get the gun to function originally.  I am figuring that everything is just breaking in and starting to run very smooth and very fast so I cut the gas out of the equation.  Let's see what another 500 rounds brings.





FIRST QUESTION:  Do you have an adjustable gas block?  If you do, try cutting gas by 3 or 4 clicks ( or till it fails to function ) and work back up.





 
10/7/2016 8:50:32 PM EDT
[#2]
LMT's don't have adjustable blocks and they are not as simple to add as other rifles due to the angle the gas port is drilled (from what I've read here).
My only option is an adjustable BCG.
10/7/2016 11:07:04 PM EDT
[#3]
I running an AAC can on my MWSE w/o problem.

You might try a heavier buffer/spring combo; I plan to but have yet/no reason to replace mine ahead of schedule.
10/8/2016 2:23:41 PM EDT
[#4]
Don't worry about over gassing. If it works, just shoot it.

Especially don't look at ejection pattern.
10/8/2016 3:07:48 PM EDT
[#5]
Like I said it worked fine for a while. Now it doesn't. Cases get stuck. Lips of case gets ripped off by ejector.
10/8/2016 3:34:46 PM EDT
[#6]
Not sure, give gene a call at lmt, he will take care of you.  

Are you running the stock buffer? When I was have some gas issues with running a jp silent capture spring supressed, they recommend a heavier traditional buffer.
10/8/2016 4:02:08 PM EDT
[#7]
I have run the stock and a heavier buffer. Both ran fine in the past.
What would a buffer and spring have to do with extracting a stuck case?
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