I have an H&R original Model 1901 ten gauge, 3 1/2" chamber, probably rechambered by a dealer who had a bunch of them for sale in the sixties. I can't remember who the dealer was. He must have bought all of H &R's remaining stock from way back. My H&R seems to like to pop open by itself with 3 1/2" shells but the gun is in near mint condition except for the Jostam pad that I installed years ago. Another great long range dove gun with 2 ounces of #7 1/2 or #6.