CarlosDJackal
02-27-08, 09:57
I recently purchased an 10.5-inch LWRC M6A1 upper (Gas piston) which I installed onto my SBR-registered RRA lower. I also set this up to accept my YHM SS Phantom suppressor (Phantom QD FH).
Last Sunday, I met a friend of mine who owned a POF upper on which he attaches a .308 suppressor (not sure what make) for a little comparison. My friend has just purchased three brand-new Magpul PMAGs, which he brought out to test as well. These were so new, he had to take them out of their individual plastic wrappings. When the POF started failing to lock open at the last round, we started looking into it closer. After a little experimentation, we determined that the new PMAGs seem to be the culprit. I tested these same magazines on my rifle and experienced the same problems. So I started keeping a video and written log of these tests. Here is what I have so far:
-- SESSION 1: February 24, 2008 --
Rifle: RRA Lower with YHM SS Phantom suppressor
Ammunition used: S&B 55-grain FMJ and UMC 55-grain MC.
Magazines tested:
Mag A. LWRC 30-round aluminum magazine [not numbered].
Mag B. Beta-C 100-round drum (clear back) [not numbered].
Mag C. Magpul PMAG [P05] manufactured: 11/07.
Mag D. Magpul PMAG [not numbered] manufactured: 02/08.
Mad E. 20-round aluminum "GI" magazine [not numbered].
Test 1 - H2 buffer with heavy spring (part of LWRC upper kit).
Upper: 10.5-inch LWRC M6A1
Mag A. No issues.
Mag B. Bolt would lock open every 1 to 5 rounds.
Mag C. Would not lock bolt open on last round.
Mag D. Would not lock bolt open on last round.
Test 2 - CAR buffer and spring assembly.
Upper: 10.5-inch LMT
Mag A. No issues.
Mag B. No issues.
Test 3 - H2 buffer and CAR spring assembly.
Upper: 10.5-inch LWRC M6A1
Mag A. No issues.
Mag B. No issues.
Mag C. Would not lock bolt open on last round.
-- SESSION 2: February 25, 2008 --
Rifle: RRA Lower with YHM SS Phantom suppressor
Upper: 10.5-inch LWRC M6A1
Buffer used: H2 buffer and CAR spring assembly.
Ammunition used: UMC 55-grain MC.
Magazines tested:
Mag A. Brownell's aluminum "GI" magazine ?].
Mag B. D&H aluminum "GI" magazines ?].
Mag C. Beta-C 100-round clear-backed drum [not numbered]. Same drum used in the previous test.
Mag D. Magpul PMAG [P01]. Marked as manufactured on: 07/07.
Mag E. Magpul PMAG [P03] windowed. Marked as manufactured on: 08/07.
Mag F. Magpul PMAG [P05]. Marked as manufactured on: 11/07. Same magazine used during the previous test.
Mag G. Magpul PMAG [P08]. Marked as manufactured on: 09/07.
Test 1 - H2 buffer and CAR spring assembly.
Mag A. No issues.
Mag B. No issues.
Mag C. No issues.
Mag D. No issues.
Mag E. Would not lock bolt open on last round.
Mag F. Would not lock bolt open on last round.
Mag G. Would not lock bolt open on last round.
Test 2 - H2 buffer and CAR spring assembly.
Mag A. No issues.
Mag B. No issues.
Mag D. No issues.
Mag E. Would not lock bolt open on last round.
Mag F. Would not lock bolt open on last round.
Mag G. Would not lock bolt open on last round.
Test 3 - H2 buffer and CAR spring assembly.
Mag E. Would not lock bolt open on last round.
Mag F. Would not lock bolt open on last round.
Mag G. Would not lock bolt open on last round.
-- SESSION 3: February 26, 2008 --
Rifle: RRA Lower with YHM SS Phantom suppressor
Upper: 10.5-inch LWRC M6A1
Buffer used: H2 buffer and CAR spring assembly.
Ammunition used: UMC 55-grain MC.
Magazines tested:
Mag A. Parson's aluminum "GI" magazine ?R] [not numbered]. 20-year old magazine with green follower and new spring installed in 2004.
Mag B. Brownell's aluminum "GI" magazine ?].
Mag C. Magpul PMAG [P02]. Marked as manufactured on: 07/07.
Mag D. Magpul PMAG [P04]. Marked as manufactured on: 09/07.
Mag E. Magpul PMAG [P06]. Marked as manufactured on: 11/07.
Mag F. Magpul PMAG [P07]. Marked as manufactured on: 11/07.
Test 1 - H2 buffer and CAR spring assembly.
Mag A. No issues.
Mag B. No issues.
Mag C. Would not lock bolt open on last round.
Mag D. Would not lock bolt open on last round.
Mag E. Would not lock bolt open on last round.
Mag F. Would not lock bolt open on last round.
Test 1 - H2 buffer and CAR spring assembly.
Mag B. No issues.
Mag C. Would not lock bolt open on last round.
Mag D. Would not lock bolt open on last round.
Mag E. Would not lock bolt open on last round.
Mag F. Would not lock bolt open on last round.
It almost seems like there is some strange dynamics between the gas piston upper, suppressor, and the polymer magazines. I do have videos of each test, but their size make it prohibitive to attach. If I manage to reduce their sizes, I will. I also plan on conducting more tests once I receive the new spring LWRC is supposed to be sending me (the one that came with the kit might be bad). What do you guys think?
I have sent Magpul an e-mail about this but have yet to hear back from them.
Last Sunday, I met a friend of mine who owned a POF upper on which he attaches a .308 suppressor (not sure what make) for a little comparison. My friend has just purchased three brand-new Magpul PMAGs, which he brought out to test as well. These were so new, he had to take them out of their individual plastic wrappings. When the POF started failing to lock open at the last round, we started looking into it closer. After a little experimentation, we determined that the new PMAGs seem to be the culprit. I tested these same magazines on my rifle and experienced the same problems. So I started keeping a video and written log of these tests. Here is what I have so far:
-- SESSION 1: February 24, 2008 --
Rifle: RRA Lower with YHM SS Phantom suppressor
Ammunition used: S&B 55-grain FMJ and UMC 55-grain MC.
Magazines tested:
Mag A. LWRC 30-round aluminum magazine [not numbered].
Mag B. Beta-C 100-round drum (clear back) [not numbered].
Mag C. Magpul PMAG [P05] manufactured: 11/07.
Mag D. Magpul PMAG [not numbered] manufactured: 02/08.
Mad E. 20-round aluminum "GI" magazine [not numbered].
Test 1 - H2 buffer with heavy spring (part of LWRC upper kit).
Upper: 10.5-inch LWRC M6A1
Mag A. No issues.
Mag B. Bolt would lock open every 1 to 5 rounds.
Mag C. Would not lock bolt open on last round.
Mag D. Would not lock bolt open on last round.
Test 2 - CAR buffer and spring assembly.
Upper: 10.5-inch LMT
Mag A. No issues.
Mag B. No issues.
Test 3 - H2 buffer and CAR spring assembly.
Upper: 10.5-inch LWRC M6A1
Mag A. No issues.
Mag B. No issues.
Mag C. Would not lock bolt open on last round.
-- SESSION 2: February 25, 2008 --
Rifle: RRA Lower with YHM SS Phantom suppressor
Upper: 10.5-inch LWRC M6A1
Buffer used: H2 buffer and CAR spring assembly.
Ammunition used: UMC 55-grain MC.
Magazines tested:
Mag A. Brownell's aluminum "GI" magazine ?].
Mag B. D&H aluminum "GI" magazines ?].
Mag C. Beta-C 100-round clear-backed drum [not numbered]. Same drum used in the previous test.
Mag D. Magpul PMAG [P01]. Marked as manufactured on: 07/07.
Mag E. Magpul PMAG [P03] windowed. Marked as manufactured on: 08/07.
Mag F. Magpul PMAG [P05]. Marked as manufactured on: 11/07. Same magazine used during the previous test.
Mag G. Magpul PMAG [P08]. Marked as manufactured on: 09/07.
Test 1 - H2 buffer and CAR spring assembly.
Mag A. No issues.
Mag B. No issues.
Mag C. No issues.
Mag D. No issues.
Mag E. Would not lock bolt open on last round.
Mag F. Would not lock bolt open on last round.
Mag G. Would not lock bolt open on last round.
Test 2 - H2 buffer and CAR spring assembly.
Mag A. No issues.
Mag B. No issues.
Mag D. No issues.
Mag E. Would not lock bolt open on last round.
Mag F. Would not lock bolt open on last round.
Mag G. Would not lock bolt open on last round.
Test 3 - H2 buffer and CAR spring assembly.
Mag E. Would not lock bolt open on last round.
Mag F. Would not lock bolt open on last round.
Mag G. Would not lock bolt open on last round.
-- SESSION 3: February 26, 2008 --
Rifle: RRA Lower with YHM SS Phantom suppressor
Upper: 10.5-inch LWRC M6A1
Buffer used: H2 buffer and CAR spring assembly.
Ammunition used: UMC 55-grain MC.
Magazines tested:
Mag A. Parson's aluminum "GI" magazine ?R] [not numbered]. 20-year old magazine with green follower and new spring installed in 2004.
Mag B. Brownell's aluminum "GI" magazine ?].
Mag C. Magpul PMAG [P02]. Marked as manufactured on: 07/07.
Mag D. Magpul PMAG [P04]. Marked as manufactured on: 09/07.
Mag E. Magpul PMAG [P06]. Marked as manufactured on: 11/07.
Mag F. Magpul PMAG [P07]. Marked as manufactured on: 11/07.
Test 1 - H2 buffer and CAR spring assembly.
Mag A. No issues.
Mag B. No issues.
Mag C. Would not lock bolt open on last round.
Mag D. Would not lock bolt open on last round.
Mag E. Would not lock bolt open on last round.
Mag F. Would not lock bolt open on last round.
Test 1 - H2 buffer and CAR spring assembly.
Mag B. No issues.
Mag C. Would not lock bolt open on last round.
Mag D. Would not lock bolt open on last round.
Mag E. Would not lock bolt open on last round.
Mag F. Would not lock bolt open on last round.
It almost seems like there is some strange dynamics between the gas piston upper, suppressor, and the polymer magazines. I do have videos of each test, but their size make it prohibitive to attach. If I manage to reduce their sizes, I will. I also plan on conducting more tests once I receive the new spring LWRC is supposed to be sending me (the one that came with the kit might be bad). What do you guys think?
I have sent Magpul an e-mail about this but have yet to hear back from them.