I'm thinking about getting MGM to make me a .32-20 barrel for my G2 Carbine but noticed that they make them with a .308 bore rather than the .312 bore that many factory .32-20s came with.  
Has anybody used a .308 bore .32-20?  How did it shoot with factory ammo?  Did you use lead or jacketed bullet ctgs?  When you handloaded it with .308 bullets, did it make a noticeable bottleneck in the case?
I'm very familiar with the .32-20; have two Colts (an Army Special and a Bisley) and a Savage bolt action.  But I've not loaded them with .308 bullets, nor fired the factory .312 bullets in a .308  bore.