correct buffer / buffer tube application

Somebody school me on buffers and buffer tubes for AR-15s. I know that pistol length uppers use carbine buffers and the tubes can be a little shorter. 16" uppers require carbine buffers. What about 18"+ uppers? Is a rifle buffer and rifle length buffer tube required for proper operation? Can a carbine buffer be used with 20" rifle uppers?

This is somewhat like VOODOO. I keep a hand full of H, H1, H2, and H3 on hand for questions like this. Different guns want to act different, but as a rule of thumb the shorter the barrel the heaver the buffer required. Also if you go with a full auto that changes things significantly.

Does this mean that the buffer tube isn't really all that important as long as the buffer weight is correct? For example, could I run a carbine length buffer tube and spring on a rifle length upper with only changing the buffer?

Caleb C wrote:Does this mean that the buffer tube isn't really all that important as long as the buffer weight is correct? For example, could I run a carbine length buffer tube and spring on a rifle length upper with only changing the buffer?

The rifle length buffer is longer than the carbine length. It may or may not work. There are two different diamiters of buffer tubes, one is milspec and one is commercial. The commercial is the most readily available. I would recommend getting a rifle length buffer for a rifle. Everything I have is carbine length.

You can run a carbine length buffer on a full length rifle. Look at the Canadians. Their c7 rifles are basically m16a4's with a collapsible stock