will a 22-250 with a rate of twist of 1/12 stabalize a 45 grain bullett?

A 1 in 12 twist should stabilize bullets up to 55 grains. Sometimes there are bullets that won't stabilize when others will. Sierra Blitz Kings in 55 gr. need more twist to stabilize than other bullets of the same weight. 22-250's with 1 in 14 twist are very popular. They will shoot bullets up to 55 gr well. Sometimes they won't shoot the heavier ones very accurately.

I'd agree, that rate would stabilize up to 55gr, I hear a lot of guys prefer 1:14" for heavier bullets though. A lot of guys like the 1:14 anyway, but I've found that 1:12" is much better with lighter bullets.

Screw the 10 ring, keep them in the zero!!!

Im looking at a savage varmint because ive good luck with their accuracy and it comes with a 1/12 twist

Some of the previous answers seem to have it backwards!! The heavier (actually, longer) a bullet gets, the faster it has to be spun to be stable!! 1/14" is the "standard" twist for a .22/250, and will stabilize bullets no longer than the Speer 70-grain semi-spitzer. If you get a 1/12" twist .22/250, it should be OK for longer bullets like the Hornady and Nosler 60-grain and all 55-grainers, whether flat-based or boattail.

Keep yore powder dry!!