This buffer tube is 8"
The 2A Armament 8 Position Billet Buffer Tube is carbine length or 8 inches long. It has a Mil Spec extension diameter of 1.148", and thread diameter of 1.185". It weighs 3.65oz.
The Ar-15 version just says carbine length, while the AR-10 version says carbine length but states a length of 8". The carbine one weighs 3.45oz and AR-10 weighs 3.65oz. Both share the Milspec extension diameter of 1.148 with a thread diameter of 1.185.
These will work with the JP Enterprises Silent Captured buffer systems.
These are standard length tubes with more stock positions. Any platform appropriate spring and buffer will work.
These are Carbine length ( 8 inches).
Yes, this will work with the M5 lower. Buffer weight may need to be adjusted, though a standard carbine buffer should work.
Yes, these are the standard length of carbine tubes.
These are mil-spec diameter, so they will work with that stock.
Yes, the gas system has no impact on the buffer tube.