rebarreling 11.5" 5.56 upper - bolt carrier question

[the_1iviper]

i'm going to be rebarreling one of my 11.5" uppers and have most of the parts except for a bolt carrier and a buffer. pretty sure i'll be starting out with an a5h2 weight buffer but i'm not sure on the carrier. originally i was going to pick up an lmt enhanced carrier to try out but lately i've been eyeing the gemtech sbc. along with the barrel and bcg i'll be switching the buffer system out to an a5 length setup. this gun is run suppressed about 75% of the time , an aac mini 4 mostly but i also run an sdn-6 on it for low light shooting. i'm trying to keep it reliable without a can but soft shooting with one.

the parts i have so far

centurion arms 12.5" carbine gas barrel (cut down to 11.5") .065 gas port , corrected
vltor gas block
lmt standard bolt
lmt mws buffer tube (vltor a5 length)
sprinco green spring , also looking for a colt rifle spring to try also

now i just need a bolt carrier and i'm not sure which might be better for this setup. would the sbc show an appreciable difference when run suppressed or would the lmt enhanced be a better option with the smaller gas port without having to pull the carrier to switch the settings like on the sbc.

any input on which might be a better option would be appreciated , it's the last part i need to order so i can "get er done"

[Iraqgunz]

I would verify that gas port BEFORE DOING ANYTHING ELSE.

[the_1iviper]

I would verify that gas port BEFORE DOING ANYTHING ELSE.

i don't have any pin gages to measure the gas port properly but i've tried a few different sets of drill bits and a 1/16" bit fits pretty snug in the hole.

from my understanding the centurion 12.5" barrel's had a gas port around .063 . i know most shops would open the gas port up on a barrel chop but this one should have been cut/crowned/threaded only , no gas port work.

should i pick up some pin gages to measure the gas port more precisely to make sure they didn't open it up or is the drill bit a close enough measure.

[jstalford]

I have heard pretty consistently that the 12.5 port is .065.

[the_1iviper]

I have heard pretty consistently that the 12.5 port is .065.

i believe your correct and i've edited the op

i think i had .063 in my brain as that's the closest to 1/16" i could figure

i guess i'll try to find access to some pin gages to verify the port size

[scooter22]

I have 0.0635-0.065 for Centurion 12.5" in my notes.

I'd say you're good-to-go for a 11.5" 75% suppressed.

[Jwknutson17]

The 2 12.5 Centurion barrels I currently have on hand, One pins right on the money at .0650 and the other pins at .0635. The .0650 is the normal for these barrels.

[Jwknutson17]

I have heard pretty consistently that the 12.5 port is .065.

This is correct. From the 6-8 or so I have pinned of their 12.5 barrels.

[Jwknutson17]

Op, you will want to use a Colt spring on that barrel with a A5H2 and quality ammo. You will have a nice shooter.

[the_1iviper]

Op, you will want to use a Colt spring on that barrel with a A5H2 and quality ammo. You will have a nice shooter.

thanks. i had planned on starting with an a5h2 weight buffer and adjust from there is necessary. i have a colt rifle spring inbound from brownells to try along with the sprinco green.

still trying to figure out if i should just use an m16 carrier or go with an lmt enhanced or the gemtech sbc