Lmt mws 308 suppressed issues.

[81sfo]

I have a second gen MWS with dual ejector bolt ,16" chrome lined barrel . I'm having issues when I shoot it suppressed with my Thunderbeast 30p-1. The bolt will lock back after each shot . I have installed a slash extra heavy carbine buffer and their rifle length spring to try to solve the problem .Still after installing these parts the rifle shot fine for about 25 rounds and then kept locking the bolt back to the rear as before.I have not tried shooting it with the factory spring and the extra heavy buffer config only in heavy spring and xtra heavy buffer .the factory lmt spring is a few inches longer than the heavy spring I bought though.
It shoots sub moa and it cycles fine without the suppressor.
I shoot handload ammo only , 175 smk 43 varget , 168 Amax 44 varget. 175 smk 41.6 xbr .
Any advice from Lmt mws owners would be appreciated.

 

[Ramius]

I have been shooting my MWS suppressed since day one. I had feed problems with the stock spring when I changed to the Magpul UBR but once I picked up a heavy buffer and spring from Slash all the problems went away.

It eats everything I feed it from Walmart 308 150 SP to Lapua 170 Scenar factory.

Suppressor is AAC SCAR-H-SD.

Did you call Thunderbeast yet?

 

[81sfo]

Thanks for your response ,i was hoping id solve the problems with the Slash heavy buffer n spring but its not the case.No I don't see why I should call TBAC ,I've had the suppressor for two years on my bolt gun no issues of course.

 

[Ramius]

I suggest calling TBAC and LMT. It might be a problem with the gas port size. LMT would probably ask you to send the rifle back so they can check it out. I had to send a brand new LMT MRP back to them a few years back because the barrel bolt seized up and they turned it around pretty fast.

Are you using different magazines or the same one?

 

[81sfo]

I'm using one pmag I hadnt thought about about trying a different mag,I will though.

 

[Ramius]

Magpul redesigned their PMAG20LR when it was discovered some early MWS gun's bolt can hang up on the lip of the magazine bolt catch causing lockback. I'll post a photo when I get home.

Until this was announced and Mapul sent me replacement mag bodies I was using Knights Mfg mags with my MWS.

 

[Hogshooter]

I have a MWS also that I shoot suppressed with a YHM can. I am loading 175 SMKs in front of 44 gr. Varget or 43.5 of RL-15. I am using the Slash x-heavy buffer and spring also. I experienced the same issue and determined the cause to be the older PMAG that I was using. I had already modified the rear of the mag to prevent it from hitting the bolt catch but had not cut the notch quite deep enough and if I inserted the mag hard the bolt would lock back on every shot while running suppressed. If I gave the inserted mag a little tug afetr it was seated hard the bolt ran normally. I ended up just squaring off the notch on the rear if the mag and that seems to have solved the issue.

 

[garandman]

I'll simply add that it IS possible to get supressed gas guns to run flawlessly. (I know this from personal expereince) Don't lose heart (or beleive those who bag on suppressed gas guns)

Good luck. And I agree - it sounds over gassed. A smaller gas port is likely the solution to bolt over travel, and correcting port size will also reduce any blowback crap getting into your receiver area.

 

[81sfo]

I appreciate all the responses....it could very well be an older pmag ,it seems I have other mags new in wrap I will try.hopefully it is not a gas port issue. I know semi autos can run suppressed I'm gona keep trying.thank you for the responses.

 

[garandman]

I appreciate all the responses....it could very well be an older pmag ,it seems I have other mags new in wrap I will try.hopefully it is not a gas port issue. I know semi autos can run suppressed I'm gona keep trying.thank you for the responses.

You know the deal... Always start with the simplest explanation first.

If it hanging on the mag, you should be able to gently remove the mag, and have the bolt slam home.

 

[Hogshooter]

Mine was not hanging on the mag. The mag was actually barely pushing the bolt catch up so that it engaged. Just dropping the mag would not release the bolt. You had to hit the bolt release.

 

[Shane C.]

Weather or not it is the mag you should also look into an adjustable gas block.

 

[81sfo]

Hogshooter...yes now that I think about it I have to push the bolt release or pull the charging handle back to load each round.it does hang up on the bolt catch.

 

[81sfo]

I just got this lmt mws so I don't know if there's an adjustable gas block that will bolt right on Shane.

 

[Yama Arashi]

Aforementioned mag tweak

 

[Ramius]

If your mag does not look like the redesigned mag in Yama's photo contact Magpul. That mag was redesigned and released in May of 2011 and will make a difference.

If you are brave you can also make the changes yourself with a dremel.

 

[81sfo]

I have a Dremel and a mill/lathe combo ill modify if needed.

 

[81sfo]

Just looked at my mag and its the new version ,I'm stumped . It's gona be a gas problem since this only happens with the suppressor on......

 

[garandman]

It's gona be a gas problem since this only happens with the suppressor on......

^^^^ This. If only happenning when suppressed, its an overgassing situ.

 

[Talkinguns]

so what adjustable gas block options exist for the MWS?

 

[Ramius]

You are over gassed. 175 over 43 target what kind of velocity are you getting? Maybe we need to come up with a different load. The factory is going to ask you to shoot some standard ammo. If it works with reg ammo it's your hand load.

Once ammo is sorted out if you are still overgassing we have to increase the weight of your buffer or we have to start playing with the gas port.

Let's go back a step. Have you removed the barrel on your mws for cleaning or something like that? If so I'd try removing the barrel and carefully reattaching the barrel, using a good torque wrench -- not the junk wrench that came with the rifle.

I suggest shooting a box of 168gr fed gm match and see if you still have problems.

 

[81sfo]

I've not removed the barrel yet, I did buy a snap on torque wrench per advice of some Austin shooters,I will remove it to clean the barrel once again. Already have the extra heavy buffer and spring ..that only worked for 20 rounds or so. Maybe 44 varget and 168 Amax in a lapua case is over gassin ? I forgot to chrony the shot but this weekend ill bring it with.i don't have any fgmm to try out,I'll have to look for some.

 

[jrhtx]

Before you send it back check your bolt catch. Mine had a bad spring and the catch would just flop around. If yours is like that it could jump up in recoil and lock the bolt open.

 

[81sfo]

Jrhtx thanks I will check that as well.

 

[garandman]

Maybe 44 varget and 168 Amax in a lapua case is over gassin ? I forgot to chrony the shot but this weekend ill bring it with.i don't have any fgmm to try out,I'll have to look for some.

Maybe dial down your handloads? MY book says you can drop as low as 42 gr Varget for 168's. Still, the fix is dealing with the gas. The gun should be able to accept the entire range of handload data.

 

[81sfo]

Ill try going with a conservative load see what that does,But if anyone knows about An adjustable gas block that fits the mws barrel please let me know.

 

[Jberry1003]

It shouldn't be a gas issue. Generally overgassing due to suppressor does not cause the BCG to lock back. If your mags are new it sounds like a weak bolt catch spring allowing the bolt catch to flop up due to the BCG/buffer bottoming out in the RE at an increased velocity due to the suppressor.

 

[Hogshooter]

....but the increased bolt velocity is due to being overgased when running suppressed.

 

[redhooker]

I am running an MWS with a 20" bbl and am loading my 175 smks with closer to 41 grains of varget for improved results. I also have the dual ejector bolt but by running a lighter charge I went from 10-15 foot ejections that were causing the term "innocent bystanders" to be used on the line quite frequently, to a mild 5 foot ejection with minimal brass damage and impressive groupings (no one enjoyed being on my right at the range ).I have yet to chrono the load and I am still tweaking with hopefully my final ladder test next weekend, but decided to "go low" after having favorable experience with CCAmmos gas gun loads.

 

[Jberry1003]

While its true the increased carrier speed is due to the overgassing a stronger bolt catch spring would probably fix the issue for about $2.

 

[81sfo]

Went and shot it once more and tried holding down the bolt catch see if it made a difference ,it functioned and cycled good for about 10 shots then got stuck again. I'm gona have to Call LMT see if they can take a look at it. I'm stumped ,I also switched from two different buffer springs with no difference made. Damn this thing. Lol

 

[Jberry1003]

What is it catching on?

 

[81sfo]

Bolt catch it acts like I just put a fresh loaded mag and have to pull charging handle back or smack the bolt release.

 

[81sfo]

Shot factory Blackhills ammo 175s , total disaster ! Primers blew out jammed into the trigger ,had to dig the primer cups from inside the trigger area and it was suppressed only .blackhills clocked 2425 fps.

 

[Talkinguns]

Wtf? I've never seen anything like that. I shoot the BH 175s thru mine all the time.m

 

[StoopidSlow]

Is the dam chamber too tight? there is an awful lot of gas back there sounds like. There is multiple issues here