My first 220 Swift was a used, late-1950's production Winchester Model 70 Varmint Rifle. After awhile, I discovered that it wasn't going to get much better than when I started insofar as accuracy was concerned, at least not with 50-grain bullets being steamed out of the muzzle at an estimated 4000 feet per second. The 55-grain bullets weren't any better, but that somewhat shot-out barrel woke up for the next several months when using Sierra's 63-grain semi-pointed bullet. My notes are long gone, but I think the powder was a middle-of-the-road charge of IMR-4350. Lesson learned? Be very barrel-condition wary when purchasing a used rifle of most any chambering, but especially if it has a reputation for being a "barrel burner." It was during this period of my life that I was taught to "read" barrels by an expert. At the time, bore scopes were not available, but close-up reading glasses in focus at varying distances were. I still use that method today to get a good quick look at the chamber and throat.
The Swift can be quite hard on barrels, with early erosion showing up in the throat and leading portion of the rifling when only hot loads are used. After a couple more used Swifts with better barrels, including a "skinny-barreled" Model 70 Sporter, I began to learn that barrel weight is not a guaranteed accuracy factor. The sporter outshot both of the heavies by quite a margin, because it had a better barrel from the git go. As the years went by, it was Swift after Swift. More Winchesters, including Custom Shop rifles; Ruger No. 1s and model 77s; Savages with their one-in-12 twist; a couple of custom-built rifles using FN Mauser single-shot actions; Remington 700s of various configurations; and, finally, Remington 40-Xs. That's where I've stopped.
The 220 Swift has what looks like a rim, but it isn't one in the technical sense of the term. Said to have been developed off of the old 6mm Lee-Navy cartridge, which hardly matters, the Swift body at the back end (case head) measures 0.445 inches. There's no convenient bolt face that size, so it was given the same diameter "rim" as a whole bunch of other cartridges; 0.473 inches. Now the bolt couldn't tell if it was hanging onto a 30-06, 257 Roberts, or any others with that standard-sized head stamp. Such a case is called semi-rimmed.
Here's what I've learned, for me. If some reader wants to believe it and skip a lot of steps I took in the process of getting here, so be it. If that person is ultimately unhappy with my conclusions, I don't want to hear from him (or her). Well, maybe her. The thing is, my doctor tells me that I'm allergic to pain, and to people yelling at me:
I no longer regard the Swift to be at its best with a 14-inch or 12-inch twist. Shooting lighter bullets very fast, say 55-grainers in the neighborhood of 3700 to 3900 fps, is okay; however, your chrome-moly barrel will have taken quite a beating at about 1500 rounds, and the 400-Series stainless will be at that point in 2200 rounds. I have regularly shot as many as 800 rounds over a three-day weekend, and I like barrels to last longer than a month. So, I've switched tasks for the Swift; it has become my long-range 22 centerfire. I do this using a Remington 40-XB in any of several styles, including the KS, the Thumbhole, the regular Rangemaster, and the flat-bottomed BR, and always ordering them with the 8-inch twist. The lightest bullet I shoot is 75 grains, but most of the time it will be an 80 grainer. Do not expect spectacular varmint hits with these more-sturdily built bullets moving at this velocity. Do, however, prepare for hits at remarkable ranges. Yes, 1000 yards. And here's another wonderful side benefit... At the 3200 fps or so you'll settle in on, you'll find that barrel fouling is much reduced. Drop down a little more to reduce chamber pressure, and barrel life will be extended.
I don't want any undertow of comments about the Swift not being hot enough to do the long-range job. Fact is, it's just right. I've been to the mountain top and gazed into the valley of discarded barrels. I built my first (and last) 22-284 maybe 30 years ago. It shot 80-grain bullets faster than the Swift, 250 fps faster, and ran along just fine for about 400 rounds. By that time I already had a 224 Clark come and go. It was good for 700 rounds at 3400. Lots more powder than the Swift, but little gain. There are some who say the 22 in a 6mm Remington case is big medicine. It is. Much like the 224 Clark, but without the case being blown out to almost straight, plus the sharper neck, the 22-6mm also make about 3400 fps at the expense of barrel life. For a 22, the Swift case is enough. And, because there are already so many excellent 22s that work well out to about 400 yards, there's no need to restrict the Swift to the short and intermediate shots.
It's easy to re-barrel a Remington action (use a short action), and Swifts do feed reasonably well through a bolt-action repeater, despite whines to the contrary. Go for at least 26 inches, because you'll be using slow-burning powder with heavy bullets. I'm using H4831 SC. Skinny is okay. It's more than okay. If you get that bedding just right, about seven to ten pounds of up-pressure on those "V"-block buttons of Steel-Bed you've carefully formed in the forend of your old-fangled wooden stock, you'll have a ball making your free-floating, fat-barreled friends eat crow. Contact Northwest Magnum by E if you have questions or comments. Remember, no yelling.