Greetings. I had a S&W 629-3 for many years. My bear load was/is a 285 grain hard cast w/gas check loaded with a near max load of H110. It was very accurate and didn't recoil badly at all.
The -3 got stolen and I replaced it with a -4, with the same 5" barrel and full barrel lug. The -4 has tighter cylinder charging holes (at the barrel end). In fact, it was difficult to seat the hard casts in the cylinder fully. However, once in place, they were just as accurate as they had been in the -3...
Because I was concerned that possibly a not fully seated cartridge would cushion a primer strike and because it took a rap on the extractor rod to dislodge unfired cartridges in a partially fired cylinder, I took emery cloth and carefully "sanded" the side of the hard casts (near the meplat). Now they seat fully with no pressure.
Am I apt to cause a problem or create a safety concern shooting these tight hard casts in this revolver? Extraction of the fired cases shows no pressure signs.