I never had a lot of luck with 55s in my 3 swifts, much better with 50s. One exception. One gun liked 44 grains of IMR 4831 under a 55 grain ballistic tip ... probably used Fed 210M primers, definitely WW cases.
The one I had that I shot the longest lived on 50 grain ballistic tips and 43.5 grains of H380, again, WW cases and Fed 210M primers. Half inch groups at 3987 fps average. It was SERIOUSLY hard on whatever got in front of it.
Tom
