My recommendation is an H2 or and H3. I run an H3. It weighs about 5 oz, which is close to the rifle buffer. The 3 oz will work OK as long as you stay with 250 grain factory loads. If you use heavier slower bullets, it is best to lock the action up longer to allow the pressure to subside before the action starts to open.
In fact, I went out this afternoon to the range and shot some Remington 405's over 27 grains of LG. Not only do I run the 5 oz buffer, but I also add the Tubbs weighted carrier system, so I am running 8.5 oz total. Everything runs fine and it was "0" degrees today
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Another benefit to running a heavy buffer is the chambering action is slowed up too. I did some tests a couple of years ago regarding bullet jump during chambering. Using a 3.0 oz (or was it 2.8) buffer, the bullets jump 0.005 to 0.006 inches. I cut this in half when I went to the heavy buffers.
Go to "www.heavybuffers.com"