The .220 Swift is a very interesting cartridge. I used it extensively when I was really into varmint hunting in the '50's and '60's. It is the old Lee Navy 6mm necked to .22 caliber. It has a semi-rimless design, so that the rim, which is slightly larger than the body, is about the same size as a typical rimless (.30-06, etc.).The tapered body and gentle shoulder slope do not lend themselves to high pressure friendliness. If one is inclined to load very hot, neck splits, and thickening can be a real problem. Originally, it was brought out in a factory loading with a 48 grain bullet so that they could advertise velocities over 4000 fps. But, in my experience, this loading was not very accurate. Using bullet weights of 52-55 grains (my favorite was the 53 gr Sierra hp), andloading for a velocity of about 3800helped the accuracy tremendously.

During those years, I also used the .22-250 (then a wildcat, made by necking the .250 Savage case to .22 cal) and found it to be easier on cases, but, in a quality rifle,no more accurate than a sensibly loaded .220 Swift. These days, I would probably opt for the .22-250 since cases are cheaper, and much more readily available, but, in its heyday,I truly loved the .220 Swift.