What kind of barrel life can I expect with this round. I'd like to build one with a 1:9" twist to shoot heavy bullets at 3100-3300 fps.

I can only say that I had a Ruger .22-250 that went 2500 rounds and was still shooting 5/8 inch groups at 100 yards when I sold it.

This particular rifle shot best with loads which did not appear to give excessive pressure, but they were sure right at the top of most load manuals (and a bit over the top loads in a manual or two).

Mine was only a factory Ruger barrel (this was an older Mark I, so barrel quality varied widely). I have been told that a smooth custom barrel will last longer but I am sceptical about that!

jpb

I "invented" my own wildcat based on a shortened 6.5 RM case necked to .22 with a 1-9 twisted 26" SS barrel.

It may have lasted 1200 shots or more. The idea was to make the .224" bore do what the 243 does. I even found someone, now out of business, who made some 88 gr partition bullets for it. These were semi pt bullets that stabilized and were accurate.

The only real negative was that it would not shoot the 80 gr Sierra or 75 gr VMax. The twist was just too slow. Not to mention that making brass was a PIA after the intial fun. Oh yes one more thing. What with the new 55 gr bullets the 243 Win will do anything that my wildcat would do with less effort.

The idea of a 22-250 is a much better, easier idea. I would use the Swift myself but at least you have picked a good one.

The twist should be 1-8" and not 1-9".

Properly cared for there's no reason to expect less than 5,000 rounds of accurate life.

I have no knowledge of my own on the topic, but someone on the board published some graphs from Browning, showing marked deterioration after 750 rounds, and comparing that with a chrome lined barrel that lasted much longer.