My curiosity piqued by recent discussions about buffers & REs, I tested a carbine weight buffer in a suppressed 11.5" upper. The upper is from my Wolf Pup pistol. It has an 11.5" barrel from PSA, standard BCG, SLR adjustable gas block and an Omega suppressor directly threaded to the muzzle. The lower uses a pistol type carbine RE with H buffer and Colt action spring.

The gas block is adjusted so the Wolf Pup will lock back on the last shot and will do so even with heavy fouling. The action is kept lubed by applying a couple of drops of oil every few hundred rounds. Closing the SLR one click usually means the Wolf Pup will eject but not lock back. On the day of the test, the Wolf Pup was heavily fouled but freshly lubed. Temps were the high 20s. Closing the gas block one click with the H buffer resulted in the round firing but did not cycle the action. Opening it back up one click restored normal operation.

I installed the carbine buffer and performed a lock back check, that is, I loaded a single round in the mag. loaded the rifle and fired. As the buffer was lighter, I expected recoil to feel a little sharper from the buffer hitting the RE faster. The action seemed a little quicker, but not enough to feel any sharper. I closed the SLR one click and did another lock back check. To my surprise, the rifle didn't cycle at all. I repeated the same check with the H buffer and got the same results. Under these conditions, there was little difference between the carbine and H buffers. The action seemed to cycle just a little quicker with the carbine buffer, but that is just a guess on my part.

I also have a Colt 6933 lower with an A5 RE and A5A2 buffer. Running the Wolf Pup upper on the Colt lower, I need to open the SLR one click to get a lock back. The 6933 upper also wears an Omega suppressor and uses a BRT .063" micro port. Function on the Colt lower is just right. I didn't test the Colt upper on the Wolf Pup lower because it was late in the day and the temps were dropping with the setting sun. I didn't test the H2 buffer because I forgot to bring it along. Next time, I will.

In conclusion, the carbine buffer worked just fine with the gas flow adjusted to match. The gas block setting was the same for both the carbine buffer and the H buffer. I was unable to test with the H2 buffer. However, I believe tuning a suppressed 11.5" to run with a carbine buffer is less than ideal as there is evidence that tuning a suppressed upper to run with a heavier buffer reduces fouling in the chamber. I think Bufford T. posted something about it. I'm going to get some heavier buffers and test them.