ok so I got the PSA 8.5" 300 Blackout barrel for 80 bones. What else do I need to build my upper? I wanna go cheap. Would this be a good barrel to use with my 9mm suppressor?

I'm gettting the same barrel. I wish I could find more reviews/specs on it before I buy but for $80 its hard to pass. I really wanted the melonite version, but I'm trying to get the upper done before I go on a camping/shooting trip next month. Funds are limited for this build and if I try and wait for the melonite one to go on sale, I may not be able to get it in time for my trip.

You will need:

Stripped upper (look for blems)
Upper build kit (FA/Dust Cover)
Handguard
Barrel nut (if your handguard doesnt include one)
Gas Block
Gas tube/gas tube roll pin
and muzzle device

plus lots of ammo!

Be sure to post pics when you get it built!

What he said.  That barrel has a pistol gas port, so keep that in mind when you shop for gas tubes.

Anderson has stripped blem uppers for $45.  That's a good start.  I like setscrew gas blocks for short barrels; they keep choosing a hand guard simple.

I bought one a few weeks ago.  It shoots, hard to say how well at this point.

Looks good. Can't wait to get mine and see how well it does. When I get mine put together I'm going to throw a scope from one of my other rifles on it and see how good I can make it do at 100 and 200, which is probably the farthest I'll ever shoot with it. In the long run it will probably end up with a red dot of some sort, although a 1-4x scope might be cool too.

OP: in my first post I forgot to mention you might also need a BCG and Charging Handle. Or you can just "borrow" them from one of your other guns, which is what I plan to do until I can afford to get a dedicated BCG.

Hey OP, you get your barrel yet? Mine showed up today!

My first thought? Damn this thing is heavy. I'm guessing stainless is heavier than CrMoV or other barrel steels? I've never owned a stainless barrel before so I didn't know what to expect.

Still, I mocked it up with some spare parts to get a feel for it, Just as good if not a little better balanced than my 10.5" 5.56 with corresponding cans on each. Overall, I think it will be fun, which is why I wanted it.

I got it and it is kinda heavy for such a short barrel. I bet it could be lightened if someone had the proper machines. I don't. I think I have all the parts needed to build except the handrail. Not sure which way I want to go with that yet. I have some flattop receivers here and I got the SDTA brake so I can use my 9mm suppressor, also have bolt carrier groups since they are standard 5.56.