What buffer, buffer spring and bolt carrier for my build?

[KiloSierra]

I'm building a 9mm pistol on a PSA Colt style lower. I've got a BA 11" barrel and upper receiver ordered for it but I have no idea which bolt carrier and buffer/spring combo I should get. Any suggestions would be highly appreciated.

[Todd.K]

The bolt should be ramped. I don't have a brand preference, just get one from a reputable source.

The standard is a 9mm buffer and carbine spring. Because it's blowback don't use anything lighter. You can use an H3 buffer if you have one.

I prefer the A5H4 buffer. (Just the A5 buffer, not the A5 buffer tube) It's heavier and longer so your bolt catch won't take as much abuse.

[hk_shootr]

You also should pay attention to the space between the bolt face and the bolt stop when the bolt is retracted all the way to the rear with the charging handle. Ideally, you want to limit this space to about 3/8". The mass of the bolt and buffer will batter the slot stop, often shearing it when the weapon is shot to empty.

[KiloSierra]

I got the parts ordered and they came in this week. Now I'm going through the joys of putting together a non-standardized AR type using parts from different manufacturers. So far tweaking the ejector to fit the bolt properly, widening the area where the mag fits into the upper so the mags drop fee and shortening the bolt stop are the only issues encountered. Now I just need a 5.5" muzzle devise to pin to the muzzle to wait until I can get the money and paperwork done to SBR it.