Re: LMT MWS Rifle Gas vs SR-25 EMC/ECC Rifle Gas
To buckjay:
I haven't handled either rifle, but the gas system for the 20"/18" LMT barrels seems to be basically same length as the 16" KAC EMC barrel. Both sit just in front of a 12" rail. There might be a slight difference in the gas tube length, bt probably a 0.5" or less.
Essentially what you are asking is if you chop 2" off of an 18" LMT barrel or 4" off of a 20" barrel will they still function like the KAC EMC. The thing to keep in mind is that there is more involved than just the length of the gas system and the overall lenght of the barrel.
You want enough gas to get to the action for the gun to function properly. Not undergassed (i.e. not short stroking, or failing to go back into battery), or overgassed (excessive recoil, excessive bolt wear, harsh or inconsisten extraction). The amount of gas getting to the action is a function of:
1. gas tube length
2. length of barrel between gas port and muzzle
3. gas port diameter
4. gas block/gas block seat diameter
Even thought the LMT gas system length will essentially be the same as the KAC EMC, you will be shortening the barrel past the gas port and reducing the amount of gas getting to the action (may result in the gun being undergassed). Also the LMT gas block is a larger diameter than the KAC. A larger diamter at the gas port typically requires a slightly larger diamter gas port in order to get the same amount of gas to the action as the smaller diameter gas block.
To answer your question of will it work? It is hard to say. Since the previous poster says the LMT is a bit overgassed the it may be just fine after the chop. The LMT gas port diamter may need to be opened up a bit to ensure the action gets enough gas.
Best advice is to ask around in the gunsmithg section of this forum and others (AR15.com, M4C.net) and see if anyone has done this already. You can check with ADCO if they have done this modification yet, and how it came out. You could also try and track down the specs on the gas port diamters for both barrels to see how they compare.
Good news is that the longer gas system on the 16" barrel should help with recoil and inherent accuracy, or at least in theory they should. Probably the reason KAC went with that setup on the 16" in the first place.
