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Cutting down LMT CQB 16" Upper to 12.5"?
- Thread starter Winny94
- Start date
- Mar 15, 2018
- 1,269
- 5,062
What’s the driving motivation for the cut mid-length gas 12.5” barrel vs using something like the factory 11.5” DI MRP Barrel or 12” piston barrel?
The piston guns are heavier and they have a different recoil impulse that not everyone likes I'm told. A midlength chopped to 12.5 is most likely going to be softer shooting and just as reliable with most common ammo as a 11.5 factory gun. LMT seems to run fairly large gas ports.
For me, LMT doesnt make a ~12" barrel and I want more than a 10.5"
As previously noted, LMT does make a 12” barrel, but it is a piston.
LMT also offers an 11.5” factory MRP DI barrel
Is 0.5” more worth the work for a non-standard barrel?
I’m just trying to get an idea what role this custom barrel plays when compared to LMT’s factory offerings. I have each of the noted MRP barrels and a number of 16” that could serve as the basis for a cut.
paying $450-$500 for a barrel and having to sell the other at $300 + time & shipping costs didnt seem worth it vs $100 to chop down a 16"
Have 10.5”, 11.5”, 12”, 14.5”, and 16” barrels. 12.5” is the shortest length that works correctly with a Surefire Mini can. 12.5” with mini is the same general OAL as 10.5” with regular SF Socom can, but with 2” more barrel.
Piston is a nonstarter.
With mid gas, no. This was for a specific task- shortest length that works correctly with Surefire Mini suppressor, with the longest port life, smoothest impulse, and absolute reliability in below zero temperatures with specific ammunition. Have no idea if commercial 223 ammo will work in this configuration or not.
Those are impressive uppers! I have a two New Zealand LMT's that I love except the 16" is a bit heavy for me and it was extremely overpassed with the LMT enhanced BCG....I switched to H2 buffer and a geissele buffer spring and its better but i haven't developed total confidence in it....I still prefer the knights... I use a variety of cans (mostly Dead air Sandman's, Rugged Surge and the KAC cans)...who did the work for your uppers? they look absolutely fantastic....how much difference was there between the 11.5" and the 12.5" when using the surefire mini....? I use the dead air sandman K's a lot and really enjoy them....my favorite are the Kac but they are proprietary so i make do.....thanks for heads up..
D Wilson Manufacturing seems to do good work, and is who I would use commercially.
LMT’s are gassed to work Worst case scenario, I.E., low pressure ammunition in extremely cold or sandy environments with dirty guns. With low back pressure cans they work fine.
The difference between 11.5” and 12.5” with the Mini is unacceptable flash and sound reduction with 11.5”, and acceptable flash and sound reduction with 12.5”. They’re not personal guns. They were built to offer the shortest suppressed OAL, with the highest muzzle velocity, longest port life, and acceptable precision specifically with M855A1 in extremely cold environments.
Thank you! I respect your Insight and the research as you obviously have come up with a firing solution that works extremely well with your gas system.
Love those uppers!!! just curious what your buffer tube And buffer springS! . Love those uppers just curious what your buffer tube is And what type of buffer spring you use? Typically LMT sells everything with a Semi automatic bolt carrier group and a carbine weight buffer tube...I’ve written letters to Karl Louis asking him why in 2020 they’re still using semi automatic bolt carrier group’s.
That’s the one knock that I have on them other than that they produce hi quality equipment!
Cheers!
Love those uppers!!! just curious what your buffer tube And buffer springS! . Love those uppers just curious what your buffer tube is And what type of buffer spring you use? Typically LMT sells everything with a Semi automatic bolt carrier group and a carbine weight buffer tube...I’ve written letters to Karl Louis asking him why in 2020 they’re still using semi automatic bolt carrier group’s.
That’s the one knock that I have on them other than that they produce hi quality equipment!
Cheers!
By the way wicked cool man! that is super awesome. You’re lucky that you’re able to see some of them! I’m gonna take an educated guess and say they’re probably manufactured for the New Zealand military because up in the mountains it’s extremely cold LOL....
God bless America and the HELL WITH THE CHINESE COMMUNIST PARTY!Hodge guns are awesome. I’ve got multiple. However, the barrels do not shoot A1 any better than any other barrel. They last, but precision isn’t what was needed. There is something with LMT barrels, lockup, and the angled gas ports they have. When shooting multiple 10 round groups, and not discounting “fliers”, every other upper/barrel that was tried averages between 4.5 and 6 MOA with A1. LMT’s somehow shoot A1 between 2 and 3 MOA. Maybe a Hadge barrel in an LMT would shoot better, don’t know. It’s far easier to get LMT barrels.
Interesting. I was under the impression mid with anything shorter than 14 required tuning. I purchased several MARS uppers when Brownells was whoring them out. Def going to have one chopped now.
Quick question for the people who have cut their 16" barrels down to 12.5, have you tried off the shelf 223? does it cycle?
While I can not speak for why they chose that set up, as temps drop, pressure falls as well, while a smaller port may run well at ambient temps, I am not sure that I would want the smallest port possible if I was planning on running in low temp. Especially if there is a chance that 855A1 may not be exclusively the diet.
Personally speaking, I would rather run at higher operating pressures with a way overbuilt bolt than to run a lower pressures with a standard bolt. Durring the IC test, the E Bolt did not see any issues with cracked lugs until they past 20k, where as most of the other guns were losing lugs around 8k or so.
