i would expect you to plug one with the 30-30ai to start with.but a 300 or 338 mag. would be AWESOME!on ed's contenders site the other night i saw a 7mm mag "hunter"barrel it was 16"or 17",the price was reasonable.good luck jim257(i still can't beleive your going out behind the 30-30 ai's back and looking to cheat on her!she probably has no idea,doe's she?)