Previously, if you wanted to use a collapsible carbine stock on your 20″ AR-15 with rifle length gas system you didn’t have many choices. You could do what I did for years and use an H3 buffer but in certain situations, this can be less than ideal or you could use the VLTOR A5 system. The H6 buffer was specifically developed to fill this role but they were relatively difficult to find until recently when Damage Industries introduced their new H6 Buffer Upgrade Kit.
The kit comes with everything you need to reliably operate your rifle upper with a carbine receiver extension – the 5 ounce H6 buffer, a 4 position receiver extension, a castle nut, an end plate, and a buffer spring. I firmly believe that 20″ barreled AR-15s with rifle length gas systems are still a very good choice for a general purpose rifle (maybe even the best choice) and they are even better with a collapsible stock.
Check out the H6 Buffer Upgrade Kit from Damage Industries.
Absolutely agree. 20″ barrels provide more velocity and greater functionality. For those concerned about the 4″ or so of added length in tight spaces, try the “Rhodesian ready” position.