I am running an Lmt mws 308 16 inch barrel with an aac 7.62 sbn6 can. Ubr gen 2 stock. I’ve tried multiple combinations of buffer and buffer springs and have finally resorted to using an adjustable gas key to control over gassing I was wondering if going to the 18 inch barrel would make a significant difference due to the extended gas system
Rifle length gas systems Run smoother than the gas system LMT uses so going to an 18 might work out for you. I know that my GEMTECH GMT 300WM would run fine with my 18 SS 308 and my 20 inch 6.5CM, but was pretty violent with my 13.5 and 16 inch barrels.
I ended up mounting my Sandman K on my 13.5, and its great, zero issues
With that being said, I think that many of us may be approaching the matter from the wrong side. In regards to LMT barrels being over-gassed, yes and no. The LMT was designed to basically fire any ammo and any environment, this ranges from Radway Green Machine gun ammo to Lake City 175's. so in order to get 147 Machine gun ammo to work at -60 some sacrifices need to be made, such as over gassing the system.
So when these rifles are shot on the civilian side of the house, people mount silencers from companies that historically chased maximum Db reduction, and as a result the gas pressure/ bolt velocity goes through the roof. and the system is no longer reliable.
In an attempt to fix the matter, people introduce more moving parts into the system with varying levels of quality control, in order attain a functional weapon.
So rather than take than changing out any of the weapons core components, I think that it would be both far more effective just running a can that was designed for minimal back pressure. Surefire, Knights, LMT, Dead Air, OSS and many other manufactures have silencers that have been engineered to have a minimal impact of the operating system.
You will then have a weapon system that is just as reliable suppressed or suppressed with any ammo.
I think that adjustable gas systems have their place, but i am not sure I would feel too confident with a clamped on hobby grade gas block, that is adjusted down to the ragged edge of reliable function just to be able to run an older/high pressure can.
people will spend 500 to a 1000 dollars fucking around with spare parts, and custom barrel work, and not give two seconds thought to a new can that would solve the issue.
Horrible Silencer/Barrel Combo
Awesome Silencer/Barrel Como