If you want to rechamber you 32 mag barrel you might want to look at a 32/20. It has a 1.5 grain or so volume advantage over a 30 carbine and seems to be a little more accurate. I have both and both are .308 groove diameter and both have a 1:10 twist. The early , octgon 30 carbines were 1:18 or 1:16 dont remember which but slower twist and would not shoot anything heavier than a 110 accurately. The 30 carbine does have an advantage that Lee makes carbide dies for them. You might want to cantact Ed and see if he can find you a 30 Carbine barrel with out rechambering your 32 Mag because they do have some collector's value.
Good luck and they are , 30 carbines & 32/20's , fun barrels and the 90 gr .308 XTP's are good bullets for them over a healthy dose of H110.