LMT MWS Suppressed Over-Gassed Fix? Part 2

Saf3sh00t3r

Gen. Ho Lee Faak
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  • Feb 10, 2017
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    San Antonio, TX
    Hello,

    Some time back, I got an LMT LM8MWS. The thing was beating up brass, so I got the crazy idea to start messing around with the Gem-Tech Adjustable Carrier. In addition to that I changed the SOPMOD with a PRS as well as added a Heavy Buffer and Rifle Legth Spring from Heavybuffers.com. Clint was very helpful.



    IMG_3118_zpskleoqmuq.jpg


    I think for most users that have this platform with both .308 and 6.5cm barrels. The heavy buffer is probably enough manage the rifle being over-gassed when suppressed. In addition, if you decide to go the carrier way it will work well with a JP HP bolt. That thread can be found here:

    http://www.scout.com/military/snipe...s/14432368-lmt-mws-suppressed-over-gassed-fix

    All that said...all that tinkering, yes I love to tinker, it wasn't enough especially when I started reloading specially to that rifle. I started running hotter loads and the gun was still beating up brass. This is because the Gem-Tech BCG only has two positions on/off.

    IMG_3109_zpswqprj34b.jpg




    Was reading an article about the Petra from Falkor Defense, I called them too, they use in the Petra an adjustable gas key.

    That's when I decided to tinker again...I found a sun devil manufacturing Adjustable Gas Key, I found online an article:

    http://www.thefirearmblog.com/blog/2015/01/28/sun-devil-mfg-adjustable-gas-key/

    After purchasing and installing it I was now able to tune my gas key to the hand-load. This isn't as good as a AGB, but I figured WTF why not? Its not as good as an SLR or a tunable system like F&D... Yet...This thing works great and it is a piece of cake to install and its about $60 or plus shipping.

    Here is my LMT BCG:

    8ADF7C03-E529-4987-9072-D387CDDAA53E_zps2gy3l4sx.jpg




    Just though I share this. It makes it much easier to taylor to your load/ammo.


     
    Re: LMT MWS Suppressed Over-Gassed Fix? Part 2
    10/04/2016

    How was getting the old gas key off?

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    saf3sh00t3r
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    XFirst Sergeant
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    Re: LMT MWS Suppressed Over-Gassed Fix? Part 2
    10/04/2016 Last edited 10/04/2016 by saf3sh00t3r

    Not an issue at all. The key was staked but wasn't a problem at all. All I did is put the carrier on a vise and removed the screws.
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    HenryrifleXPrivate
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    Re: LMT MWS Suppressed Over-Gassed Fix? Part 2
    11/16/2016

    Hey saf3sh00t3r,

    Thanks for the posts about your experiments to improve this overgassed-when-suppressed weapon. Out of consideration to my neighbors, I shoot everything suppressed. Like you I have the 20" SS 5R barrel and it shoots amazingly well. I have not had the chance to push it past 600 yards yet but will soon. I have installed the heavy buffer from Clint and it does help a little. If the rifle didn't shoot so well I'd send the barrel off and either drill and tap the gas block and turn it into an adjustable one or find one that would work with the LMT barrel. Very hard to believe that LMT doesn't offer a solution or service for this issue. My brass get tossed out pretty good to the 1:00 or 1:30 position. More than that though, you can really feel the bolt slam back into battery. Overall it is a lot more violent than it needs to be.

    My chamber and upper get pretty filthy after 40-50 shots. Does the adjustable gas key make that any worse?

    Overall I am very impressed with the repeatable accuracy of the weapon but the lack of an adjustable gas block will eventually make me set it aside in favor of a more sophisticated solution.

    Thanks for your work and willingness to share,

    Henryrifle

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    saf3sh00t3r
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    XFirst Sergeant
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    Re: LMT MWS Suppressed Over-Gassed Fix? Part 2
    11/16/2016 Last edited 11/16/2016 by saf3sh00t3r

    Hey Henry, well the adjustable gas key makes it run much better, softer shooting and cycling. I also gained better accuracy because the dwell time was so much better from a reliability perspective and violent movement.

    That said, what ammo are you using? Your gun should be run wet, I use slip2000 ewl 30, which is heavier than oil. I can go 150-200 rounds without cleaning supressed. I do add a couple of drops of oil before a range session between cleaning. When I say cleaning, i take stuff apart and wipe, that's it. Haven't done White glove cleaning ever. Will do a sonic wash at about 1000 rounds.

    I am no longer going to buy LMT barrels, because of the gas block, have sent one of mine to Jeff Hayes so he can spin up a Bartlein and add an AGB. He has to canabilize the barrel extension and sleeve.

    If any reduction of filth happens it's not by much compared with no key especially suppressed. Honestly supressed will keep things dirty no matter how much you try not to. Now, I also have a Seekins an AGB does make a difference...I can go about 350 rounds without cleaning.

    I think you will be very happy with the Gas Key result.
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    HenryrifleXPrivate
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    Re: LMT MWS Suppressed Over-Gassed Fix? Part 2
    11/16/2016

    Interesting. I run handholds primarily. They are very similar to 168gr FGMM in barrel speed. I am using 168gr SMKs over 42.8gr of IMR 4064 in Lake City brass. With that ammo, the gun consistently shoots .75 MOA at 100 yards and often better.



    I do a full disassembly of the upper as well. The nastiest part of the cleaning is the bolt and bolt carrier. The tail section of the bolt behind the gas ring and the corresponding area of the carrier have to be cleaned [scraped] with a tool even after dropping them in the sonic cleaner for 30 minutes. This has never impacted reliability in any way but it is hard to image what those specific areas would look like after a few hundred rounds. I use TW25 grease on the parts of the carrier that should be greased and the back of the locking lugs on the bolt.



    I may give the gas key a try. I have seen it advertised and contemplated purchasing a second LMT bolt carrier group but that idea turned expensive and hard to find pretty quickly.



    I also have the 16" CL barrel that I would happily sacrifice to get another barrel with a proper adjustable gas block. I am also considering ordering a LaRue PredatOBR in 7.62 just because of the gas block issue.



    Thanks again for sharing. The LMT is a great weapon and aside from the gas block issue I am very impressed with its accuracy with the SS barrel.



    Henryrifle

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    saf3sh00t3r
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    XFirst Sergeant
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    Re: LMT MWS Suppressed Over-Gassed Fix? Part 2
    11/17/2016

    Cool, no worries man. I like larue stuff, thought about their rifles as well until I noticed their platform isn't ambi and their gas block is either on or off, you can't really tune it. I also believe their AGB is set for surefire and the tranquilo.

    I sent my CL barrel to Jeff at Riverbend, it takes 4 months or so. It's costs slightly more than an LMT barrel.

    Try some EWL it really made a difference for me in how often and how much to clean. PM me your address and can send you some to try.

    My LMT has been great in both 6.5 and .308. Did you change the trigger? I switched mine to the SSA-E from Geissele it also makes a huge difference in accuracy.
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    HenryrifleXPrivate
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    Re: LMT MWS Suppressed Over-Gassed Fix? Part 2
    11/17/2016

    Don't get me wrong. I am very impressed with the LMT and have no plans to get rid of it. I have the same trigger and, from the looks of it, the same scope, a 5.5-22x50 NXS. Appreciate the offer to send some EWL but can pick up locally and support LGS.

    The turn off for me about the LaRue is the wait but now that I have a great .308 semi-auto shooter, I am no longer worried about the wait.

    I agree that the AGB on the LaRue might not be ideal but it is much better than no option at all. Just toying with the idea of the LaRue--not yet committed.

    Thanks again,
    Henryrifle

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    BlackfootSeven
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    Re: LMT MWS Suppressed Over-Gassed Fix? Part 2
    01/04/2017

    After months of swapping parts and trying out different optics, components and things, I've pretty much settled into this final configuration. At one point I was going to ditch the whole DMR idea altogether, but I think the gun shines in this role above all others. At least for me. I was able to mitigate the gas issue by installing an adjustable gas key that a buddy sent me a while back. Totally forgot that I had it in my parts bin until he reminded me as we were discussing some of the issues I was experiencing with blown primers. Right now it's tuned to run M118LR optimally, and I might need to make slight adjustments when running .308 match loads. Still interested in having some custom barrel work done for a 6.5 CM option, but that's a project I'll pursue maybe later on in the year.

    Thanks, guys.



    NV1hij.jpg




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    pmclaineXFirst Sergeant
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    Re: LMT MWS Suppressed Over-Gassed Fix? Part 2
    01/05/2017

    You guys have done some great things with your LMTs, thank you for putting the results of your changes out there.

    Mine is still a vanilla 16inch CL with a cheese grater front end. Its a tank.

    It was intended to be my one "accuracy" rifle but I discovered that bolt guns are way more easier to shoot for accuracy and I have since relegated it to a fun gun to have in the inventory that is very capable.

    Regards the carbon build up...I know the stuff has been argued about as either the best thing since sliced white bread or the latest snake oil, but I have found FireClean to actually make a difference on the tail of the bolt and back of the carrier. I haven't had the stuff gum up at all either between infrequent trips to the range. Agreed price sucks but it works for me in .308 and 5.56 LMTs.





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    78thDD
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    Re: LMT MWS Suppressed Over-Gassed Fix? Part 2
    01/05/2017

    Something that might interest you.



    suparms.com/collections/adjustable-gas-blocks-direct-impingement/products/copy-of-875-adjustable-gas-block-bleed-off-solid-melonited



    The Superlative Arms patent pending “Bleed Off”, direct impingement, gas block for the AR15 platform adjusts the gas flow by bleeding the gas out of the block instead of restricting the flow like conventional adjustable blocks. Results:
    • The pressure used in the block is reduced only to the amount required to drive the bolt carrier. The remaining gas / pressure are bled out of the block allowing the system to run much cleaner and cooler.
    • Reduction of felt recoil.
    • Patent pending adjustment detent is located outside of the block and therefore no contamination.
    • The gas adjustment screw does not restrict the gas flow; therefore there is no erosion or seizing of the screw / no loss of detent due to carbon build up. Although it is removable, we have added a safety mechanism, which stops you from unintentionally backing the screw all the way out.
    • When using SBR’s and / or suppressors the bleed off port allows the excessive pressure to be exhausted out of the block reducing blow back.
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    NukeMMC
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    X95 MONTHS
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    Re: LMT MWS Suppressed Over-Gassed Fix? Part 2
    01/05/2017

    78thDD wrote:

    Something that might interest you.

    http://suparms.com/collections/adju...djustable-gas-block-bleed-off-solid-melonited

    The Superlative Arms patent pending “Bleed Off”, direct impingement, gas block for the AR15 platform adjusts the gas flow by bleeding the gas out of the block instead of restricting the flow like conventional adjustable blocks. Results:
    • The pressure used in the block is reduced only to the amount required to drive the bolt carrier. The remaining gas / pressure are bled out of the block allowing the system to run much cleaner and cooler.
    • Reduction of felt recoil.
    • Patent pending adjustment detent is located outside of the block and therefore no contamination.
    • The gas adjustment screw does not restrict the gas flow; therefore there is no erosion or seizing of the screw / no loss of detent due to carbon build up. Although it is removable, we have added a safety mechanism, which stops you from unintentionally backing the screw all the way out.
    • When using SBR’s and / or suppressors the bleed off port allows the excessive pressure to be exhausted out of the block reducing blow back.
    I have 2 of these gas blocks, one on a MK12 (Rainier Ultramatch, M16 carrier, rifle buffer and spring, Ops Inc 12th Model can) , the other on a 308 AR10 (Armalite carrier, rifle buffer and Tubb spring, Ops Inc 3rd Model can) with a 20" WOP 1:10 heavier barrel (.875" at the block).

    They work .... BUT:
    • The AR10 block at full vent will still cycle reliably. With the adjustment only 4 clicks (1 full turn) open, it locks back on an empty mag. At full vent the brass goes to 3 o'clock, same with it at 1 turn open.
    • On the MK12, the gas block acts the same as the AR10. Even at full vent, the rifle cycles 100% when suppressed.
    DO NOT use this AGB as a vent with a suppressor cover!!!
    20170101_202630_zps1akzuau5.jpg


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    saf3sh00t3r
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    Re: LMT MWS Suppressed Over-Gassed Fix? Part 2
    01/05/2017

    Any gas block replacement would be good for an LMT factory barrel, the problem is that you can't replace it easily due to diameter and gas port configuration on the barrel.

    LMT presses the GB and removing it would be like an act of god.

    So you need to either use a gas key, GemTech adjustable carrier or a replacement barrel using an existing barrel extension and sleeve.
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    HenryrifleXPrivate
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    Re: LMT MWS Suppressed Over-Gassed Fix? Part 2
    02/04/2017

    Hey saf3sh00t3r and BlackFootSeven:

    I installed an adjustable gas key in my LMT today and WHAT A DIFFERENCE!! Wish I had tried this sooner. I am ready to take out the HeavyBuffers.com buffer and spring and go back to stock as the adjustable gas key (Rubber City Armory) gives full control over the amount of gas going into the carrier. I don't know what the longevity of this component will be but no more stinging gas in my face and no more violent recoil where the buffer bottoms out inside the receiver extension. Thank you guys for trying this out and giving it a good review. I am extremely happy with the results!!!

    Henryrifle

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    saf3sh00t3r
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    Re: LMT MWS Suppressed Over-Gassed Fix? Part 2
    02/05/2017

    Henry, I'm glad it worked out for you. I used one from Sun Devil manufacturing. I haven't had any issues at all and I really like the way my rifle works with It.
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    TxFlyboyXGunny Sergeant
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    Re: LMT MWS Suppressed Over-Gassed Fix? Part 2
    Wednesday at 1:49 PM

    Where could one purchase an adjustable gas key?

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    saf3sh00t3r
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    XFirst Sergeant
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    Re: LMT MWS Suppressed Over-Gassed Fix? Part 2
    Wednesday at 1:54 PM

    https://www.dillonprecision.com/sun-devil-adigs-drop-in-adjustable-gas-key-kit_8_0_26470.html

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    saf3sh00t3r
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    XFirst Sergeant
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    Re: LMT MWS Suppressed Over-Gassed Fix? Part 2
    Wednesday at 1:56 PM

    http://shop.sundevilsales.com/ADIGS...as-System-223-308-Compatible-SD-ADIGS-KIT.htm

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    Magstang1XSergeant
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    Re: LMT MWS Suppressed Over-Gassed Fix? Part 2
    Friday at 10:15 PM

    Looking to add a suppressor to my MWS. What is everyone running?

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    saf3sh00t3r
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    XFirst Sergeant
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    Re: LMT MWS Suppressed Over-Gassed Fix? Part 2
    Yesterday at 12:15 AM

    I've run AAC 762-SDN-6 and SilencerCo Harvester Big Bore as well as a Hybrid.

    You can run anything, just be aware you're going to be more over-gassed.