Colorado Pete
New member
Howdy everyone, been a looonng time since I posted here. 
My two cents...I have a .22-250 AI, which is about the same thing (or close) as a .22-243. After about 3 seasons (~1500-1800 rounds) I am seating the bullets out an extra .025". I had the barrel (10" twist Pac-Nor) made with enough cylinder to whack the threads off and set it back when the time comes. Unfortunately, with that twist I can't shoot what I think is the best long-range .22 varmint bullet, the Hornady 75 A-Max.
But, for a long range gun, the .243 I think is better. The barrel should last a tad longer than a .22-cal, and you can use both the excellent 87 V-Max boattail and 105 (107?) A-Max. I like the A-Max's over regular match bullets because the plastic tip will initiate greater expansion, especially at long range, than standard hollowpoint match bullets (which aren't designed to expand). The real issue at long range isn't velocity or drop, but wind-drift resistance, and I think the bigger heavier .243 bullets are superior to the .22's at those longer distances. Well, a check of the back of the loading manuals will set us straight on that.
Another route is the new 6XC, used in highpower match rifles. This is a .22-250 case with the shoulder blown out a bit and necked up to .243. Not sure if the body taper is also straightened. The case capacity is I think just a hair less than a .243, which should promote barrel life a bit more. You can get cases from David Tubb, and I think either Norma or one of the domestic manufacturers is making them now as well.
Good luck with whatever you pick. If you have a custom barrel made up, have the cylinder (the part just ahead of the threads) made extra-long (like about 2" long) so that the barrel can be set back and re-fitted when you burn out the throat. Will get you a second go-around with it.
My two cents...I have a .22-250 AI, which is about the same thing (or close) as a .22-243. After about 3 seasons (~1500-1800 rounds) I am seating the bullets out an extra .025". I had the barrel (10" twist Pac-Nor) made with enough cylinder to whack the threads off and set it back when the time comes. Unfortunately, with that twist I can't shoot what I think is the best long-range .22 varmint bullet, the Hornady 75 A-Max.
But, for a long range gun, the .243 I think is better. The barrel should last a tad longer than a .22-cal, and you can use both the excellent 87 V-Max boattail and 105 (107?) A-Max. I like the A-Max's over regular match bullets because the plastic tip will initiate greater expansion, especially at long range, than standard hollowpoint match bullets (which aren't designed to expand). The real issue at long range isn't velocity or drop, but wind-drift resistance, and I think the bigger heavier .243 bullets are superior to the .22's at those longer distances. Well, a check of the back of the loading manuals will set us straight on that.
Another route is the new 6XC, used in highpower match rifles. This is a .22-250 case with the shoulder blown out a bit and necked up to .243. Not sure if the body taper is also straightened. The case capacity is I think just a hair less than a .243, which should promote barrel life a bit more. You can get cases from David Tubb, and I think either Norma or one of the domestic manufacturers is making them now as well.
Good luck with whatever you pick. If you have a custom barrel made up, have the cylinder (the part just ahead of the threads) made extra-long (like about 2" long) so that the barrel can be set back and re-fitted when you burn out the throat. Will get you a second go-around with it.