When you get around to shooting it, you then see how happy you are with it.
If the ammo you are shooting ejects out at anywhere from 2-4 o'clock, then the gas port, buffer & spring are more of less OK.
Hotter ammo like true 5.56 will eject a little more forward than lighter commercial 223.
The 3.0 oz buffer is a standard carbine buffer; an H buffer is 3.7 oz.
After you shoot it for a while, just make note of where any particular type ejects.........you will likely not be undergassed so probably no issues with bolt lock back on the last round, but it's always a good thing to load one round & verify lock back.
If you have any issue or need anything, let me know & run it wetter than drier.
And buy decent mags. I like the ACS stainless or the Brownell mags with Magpul followers, but all my plastic Magpuls have run just fine too.
MM
