Confusion with finding a correct buffer

[Clint]

Which barrel?

Thank you all for the input. I ordered an H2 and will start there. I will report back as soon as I have the rifle put together and time to shoot it.

[Bodhisattva05X]

Not sure who makes the barrels for Aero. I picked up a complete upper from them. 18” rifle length gas system. Haven’t had much luck finding out what the gas port size is. Not concrete info on their 18” barrels. Tons of info regarding 16 and shorter.

[Metric Matt]

Not sure who makes the barrels for Aero. I picked up a complete upper from them. 18” rifle length gas system. Haven’t had much luck finding out what the gas port size is. Not concrete info on their 18” barrels. Tons of info regarding 16 and shorter.

Aero owns Ballistic Advantage, so it’s a safe bet that what you are getting is a BA barrel. The SS SPR barrel I have has a .080 gas port, which is probably on the smaller side at least compared to my FN barrel and the spec for the Mk12 barrel which is around.100 if I remember correctly. I assume they did this to assure reliable cycling even though it’s probably somewhat over gassed.

[MistWolf]

What confusion? Use an H2, A5H2 or rifle buffer with the appropriate RE and spring in your 5.56

I’d start with a std. buffer and three tungsten weights, or the KAK buffer kit.
Then just swap a steel weight with a tungsten til you get it how you want.
If your build is gassed properly, it’ll probably run almost every combination of buffer weight & ammo.

Buffer weight does matter, but not the way some people think. Buffers won't make up for under or over gassing, but they make a difference in how recoil feels. The carbine weight buffer (three steel weights) gives sharper than necessary recoil because the reciprocating mass slams into the RE. Reducing gas flow won't work. It takes the same gas flow for full function whether a carbine or H2 buffer is used.

[Bodhisattva05X]

In case anyone is interested, the gas port is .0935

[Dr. Bullseye]

There are guys here qualified to do brain surgery on their rifles by altering the size of their gas port or installing an adjustable port but I am not yet that competent. It seems to me you get a KAK buffer kit and begin trial and error. It doesn't cost much even if you have to buy two more springs (which I did). Finally, you will come up with something which fits all the parameters. And if I can do it, anyone here can do it.

[Clint]

You got lucky.

That barrel will most likely run well with a simple H buffer and mil-spec spring.

Not sure who makes the barrels for Aero. I picked up a complete upper from them. 18” rifle length gas system.

In case anyone is interested, the gas port is .0935