I have a Remington 40 XBKS in .220 Swift I got from the Remington Custom Shop in the early 90's. The throat is about shot in it, and it is time for a rebarrel. I am thinking of stepping up in the power/range department since I have another nice light varmit rifle now.

My questions involve the boltface and action length. The Swift has a slightly larger boltface than all of the .308/30-06/7x57 families does it not? Is the increase in diameter enough to matter or cause any problems? Next question is action length. I am assuming the swift would still be on a short action would it not? I am seriously thinking about a 6mm/6mm Ackley, but I know they are based off the 7x57 which is really a touch long for a short action, especially if you want to run heavy, long VLD style bullets. Would the .243/.243 AI be a better match for this action? Or is there another cartridge any of you feel would be a better match than those mentioned. The rifle will serve as a dual purpose longe range varmit and whitetail rifle. What twist rate would be best, a 1 in 9"?

The 220 Swift used a .473 rim last I checked.

The boltface is the same size. You might check the 6.5X47Lapua round.
Butch

You can use any cartridge on the '06 head size (.308s or derivatives, etc.). I'm assuming you'll use it as a single shot, if so, then the 6mm or 6mm Ackley (.244 Improved) would do just fine, as would the .243 or .243 A.I. If you want to bump the power up a step further, the 6mm/284 will fit nicely, uses the same bolt face, and is slightly shorter than the 6mm case.

I would really like to keep it as a repeater. My limited searching shows the OAL for a Swift to be 2.860", the .243 to be 2.710" and the 6mm to be 2.825". I know these are factory specs, and running a long VLD style bullet will increase that. From that standpoint, it would appear maybe a .243 AI would be better, allowing more leeway with seating longer bullets.

I guess the first thing I need to do is check magazine length and go from there. Anyone know offhand what that is on a short action Remington?

The difference in the swift is just past the rim of the case at the base. the base size is .445 as opposed to a 30-06 case where the base is .471 It is a semi rimmed case but the rim diameter is the same as any 8x57 based cartridge why the hell they based the .220 swift on the 6mm lee navy I'll never know but it wasn't the best idea.

You will have to stay with a 243 or shorter length case to geep it feeding. A 1-8 twist will stabilize the 105+g VLDs.

I understand the 6mm Lee Navy case was used as the parent for the 220 Swift because of the heavy casehead design in the Lee case. 220 Swift pressures are way higher than most other cartridges of that era so finding a suitable parent case was probably not an easy task.

I've always heard that, but since Winchester was not actually making Swift cases from 6mm Lee Navy cases, they could have made them as heavy as they wanted, no matter the size.

I think it is more likely they did not want shooters to make their own Swift cases from other weaker cases, which would have happened if they made the Swift with a standard 0.473 case head.

Bruce