Does the 280 AI need a 24" barrel or is a 22" barrel long enough to get real improvement? I read an article on the 30-06 AI and Ackley said with it less than 24" isn't worth the trouble. My son has a M77 MKII 280 and was asking me about it. I've heard it is one of the most often rechamberings done. Thanks for any info on this. Dave