If you reload, there is a large variety of available lightweight .30 expanding bullets which will work in an M1 Carbine. My preference, if you want expansion, is the 100 grain .30 half-jacket Speer Plinker. You can easily exceed an MV of over 2000 ft.sec with the lighter bullet. If you don't handload, the Speer Gold Dot or Hornady Critical Defense .30 Carbine loadings are supposed to be very good. I have never encountered a feeding problem with any bullet I have ever tried in the Carbine. Even the .30/.22 Sabot bullets (Accelerator).

I have understood that accurizing a carbine is possible, but outstanding grouping improvements are unlikely. I have never been able to find a load which will do much better than 4"-5" 5-shot groups from a bench rest at 100 yards with mine, which still has a pretty fine barrel. Others may have discovered the magic formula, but I haven't. In any event, 4"-5" groups are just fine with me.

The original military specification for the .30 Carbine M1 Ball round is a Mean Radius (MR) of 1.5" or less at 100 yards. I am not sure just how many shots per group were used to establish the MR and from what kind of gun. However, the standard rule of thumb is that the MR will generally be about 1/3 of the extreme spread (ES), no matter how many shots are in the group. Therefore the expected ES would be about 4.5" under whatever the requirements of the official grouping test were. And guess what? That ES is about what the performance of the .30 Carbine M1 Ball turns out to be.