The Phase 5 Weapon Systems Inc AR-15 Pistol Buffer Tube can be used with a stabilizing brace such as the SB Tactical Pistol Brace.
Yes, this buffer tube has the same internal dimension as a standard carbine tube. You will be able to use the super 42 spring and buffer.
The tube weighs 4.8oz.. but if you are referring to a buffer weight, there is a standard carbine buffer included in the complete assembly (SKU PBT-CA). This SKU does not include a buffer.
Yes, the Phase 5 Weapon Systems Inc AR-15 Pistol Buffer Tube will have the Phase 5 logo printed on the side of the tube.
This is 7.4"
Yes, this would be compatible with .300 BLK.
That is correct. This buffer tube includes a castle nut, end plate and foam pad.