I have also heard that 30-30 brass can be used, but should be used with caution and reduced loads. I have personally never used 30-30 brass...Midway had .375 Win brass available, and I purchased several hundred rounds from them. Availability was no problem, and the price was not too bad...obviously more than 30-30 brass, but not too bad on the wallet. I forget the actual price, but I know it wasn't that bad.