I had a CMMG upper that was sent back due to light primer strikes last December. I had a failure to fire about 70% of the time. Ran it with and without the buffer and spring with the same results.
I've had the upper back since then but have not tried it out till last week. Tried it first without the pressure plug for 100 rounds and it ran flawlessly, even the BHOA worked like a charm. Installed the pressure plug and tried it for another 100 rounds. No malfunctions of any kind. Did notice a more consistent strike on the case rim with the pressure plug installed. Although my upper seemed to work without the pressure plug (thanks CMMG), i think it is still a good idea to have one installed to decrease the chance of malfunctions.
I've had the upper back since then but have not tried it out till last week. Tried it first without the pressure plug for 100 rounds and it ran flawlessly, even the BHOA worked like a charm. Installed the pressure plug and tried it for another 100 rounds. No malfunctions of any kind. Did notice a more consistent strike on the case rim with the pressure plug installed. Although my upper seemed to work without the pressure plug (thanks CMMG), i think it is still a good idea to have one installed to decrease the chance of malfunctions.

Comment