Recently while looking for a new SR25/DPMS pattern AR type rifle that would be caliber adaptable, so I opted for the LMT MWS .308. My goal ultimately was to run it suppressed and unfortunately the gun did not have an adjustable gas block, let alone an adjustable gas key…all this I already knew when purchasing it and this sent me on a quest to address the BCG speed and over-gassed issue causing stovepipes when suppressed, but the best thing about my choice was that I could change my barrel with little or no effort and to a totally different round option. I also found it to be a ¼ to ½ MOA rifle @ 100 yards with an SS 20” barrel.
The gun as of today has received basic improvements to address the BCG speed due to being over-gassed and it’s a better gun to shoot all the way around suppressed and unsuppressed.
Anyway, here is the rifle so far and below is the story as well as how I got things to work out well.
Here is the story:
In order to address the lack of being able to adjust gas left me with two options 1) replace the gas-key on the BCG to an adjustable or 2) change the bolt carrier to my only option Gem-Tech’s adjustable gas carrier.
I chose the carrier vs. monkeying around with my existing BCG’s gas key. The Gem-Tech carrier also is very easy to adjust compared to an adjustable gas key that usually requires an allen tool.
The challenge was the BCG component combination, which is when the quest began. The LMT bolt and firing pin worked “ok” on the new BC, the problem was when the bolt release on the lower was pressed the round was picked up and BANG! The round would go off due to being too far forward. The firing pin was protruding a little too much and was not floating very well. This happened primarily when using a leitner-wise retaining pin more so than others. Since this was unsafe, it needed to be fixed.
Basically the firing pin retaining pin and firing pin were incompatible with the new carrier. The retaining pin kept the firing pin more forward than normal and when the bolt would go into battery a primer strike would happen because the firing pin was not floating well. I found this was because in the LMT firing pin is shorter and the Leitner-Wise retaining pin diameter was larger and different when compared to the LMT captive retaining pin. I tried different retaining pins, such as DPMS, Larue(cotter pin), etc. the item I noticed was the firing pin was still shorter. I obtained a few new firing pins from DPMS, Larue, Knights, etc…the issue with those was the diameter of the pin at the bolt face…which was .080” or so and the LMT bolt is .068”.
The next option was to use a completely different bolt altogether, so I chose JP Enterprises High Pressure Bolt because it uses a .062” firing pin at the bolt face that would be perfect for the 6.5 CM round as well as the .308 win. The LMT uses .068”, so I figured this would be the best option. See below the differences in firing pin size.
After checking headspace, I headed to the range and with much surprise the new Bolt and Carrier combination worked quite well. At some point, prior to these upgrades, I had added a heavier buffer and new spring because of the new PRS stock. Here is my target @ 100 yards using Federal GMM 168 grain, which this rifle likes the best so far. The point of impact shift was minimal at about 1 inch, the group below was after re-zero with the Silenceco Harvester Big Bore using an ASR Break and mount.
That said, this thing has now a Gem-Tech Carrier, JP Enterprises HP Bolt, and Slash’s Heavy Buffer with rifle spring. I figured this combination would help someone else’s LMT MWS .308 saga.
The gun as of today has received basic improvements to address the BCG speed due to being over-gassed and it’s a better gun to shoot all the way around suppressed and unsuppressed.
Anyway, here is the rifle so far and below is the story as well as how I got things to work out well.
Here is the story:
In order to address the lack of being able to adjust gas left me with two options 1) replace the gas-key on the BCG to an adjustable or 2) change the bolt carrier to my only option Gem-Tech’s adjustable gas carrier.
I chose the carrier vs. monkeying around with my existing BCG’s gas key. The Gem-Tech carrier also is very easy to adjust compared to an adjustable gas key that usually requires an allen tool.
The challenge was the BCG component combination, which is when the quest began. The LMT bolt and firing pin worked “ok” on the new BC, the problem was when the bolt release on the lower was pressed the round was picked up and BANG! The round would go off due to being too far forward. The firing pin was protruding a little too much and was not floating very well. This happened primarily when using a leitner-wise retaining pin more so than others. Since this was unsafe, it needed to be fixed.
Basically the firing pin retaining pin and firing pin were incompatible with the new carrier. The retaining pin kept the firing pin more forward than normal and when the bolt would go into battery a primer strike would happen because the firing pin was not floating well. I found this was because in the LMT firing pin is shorter and the Leitner-Wise retaining pin diameter was larger and different when compared to the LMT captive retaining pin. I tried different retaining pins, such as DPMS, Larue(cotter pin), etc. the item I noticed was the firing pin was still shorter. I obtained a few new firing pins from DPMS, Larue, Knights, etc…the issue with those was the diameter of the pin at the bolt face…which was .080” or so and the LMT bolt is .068”.
The next option was to use a completely different bolt altogether, so I chose JP Enterprises High Pressure Bolt because it uses a .062” firing pin at the bolt face that would be perfect for the 6.5 CM round as well as the .308 win. The LMT uses .068”, so I figured this would be the best option. See below the differences in firing pin size.
After checking headspace, I headed to the range and with much surprise the new Bolt and Carrier combination worked quite well. At some point, prior to these upgrades, I had added a heavier buffer and new spring because of the new PRS stock. Here is my target @ 100 yards using Federal GMM 168 grain, which this rifle likes the best so far. The point of impact shift was minimal at about 1 inch, the group below was after re-zero with the Silenceco Harvester Big Bore using an ASR Break and mount.
That said, this thing has now a Gem-Tech Carrier, JP Enterprises HP Bolt, and Slash’s Heavy Buffer with rifle spring. I figured this combination would help someone else’s LMT MWS .308 saga.
