The brown truck dropped off my new PSA 11.5" upper assembly Saturday. Ever since I saw a pic of the 733 Commando I wanted to build one. Since I dont have a stamp, now I am faced with a decision to pin and weld some type of barrel extension or pistol brace it. While the SBM4 looks the most military it certainly isnt a CAR stock so the "clone" is now a 733(ish) build. I hate losing the short barrel with some kind of extension so the brace will be my choice.
Now, all I find with the xescription of the SB M4 is that it fits standard pistol buffer tubes. This will be my first AR pistol so I am a little confused as to what a "standard" pistol buffer tube is. Ive seen tubes with a bit of foam on the end and ones without the foam. They are generally a simple smooth tube and I have also seen fluted ones. Can someone please point me to a "standard" tube?