Hello NFA experts! Or... experts in building NFA goodies! I need your help! Here's the situation. I know pretty much nothing about any NFA goodies, other than what I've read about applying for the taxes. I think I have that covered. But right now, I am looking to build a CQB style thingamajig. I want something short, and something reasonably quiet. For now, I'm thinking .300 Blackout/AAC My questions: 1. What barrel length? I want it to be reasonably short, after I put a silencer on the end. Which brings up my next question... 2. How long do suppressors run for a .300? I'm thinking I will want one that can handle a .30-06 as well, so experts, please take that into consideration. 3. I've heard that pistol buffers can have problems. But... I plan to start my journey with an AR pistol build, put a can on it to see if I like it before I get a stamp for an SBR (I have no experience with these, so I might not even want an SBR [or AR pistol for that matter] after all). Is it feasible to run a carbine length buffer tube on a pistol AR, or are there no real problems with pistol buffers? So... let me know what I should do, state your arguments (civilly please), and help me build this thing! Absolutely everything is still in flux at this point, except I have a stripped lower already. Should I go with an integral suppressor and get 16.1 inches and just forget the SBR? Should I go with a 7.5 inch barrel right off the bat? I've been eyeballing PSA's pistol kits and drooling... Please note, this build is particularly in consideration for combination with the suppressor. It might branch into an SBR build in the future, but I put this in the NFA forum because I want it specifically for use with the suppressor.