Home Forums Reloading Bullet Casting What weight bullet could I cast for both 45-70 and 45-90?

Before selecting a mould you might want to confirm the rifling twist and slug the barrels to determine their groove diameter.

Marlins tend to have variable groove dimensions, but are generally on the large side. Mine measures 0.4585. I have slugged two Miroku 45/70 barrels and they were both tight, measuring 0.457.

Sizing your cast bullets on the larger side is fine as long as the loaded cartridges still chamber easily.

I like using RCBS 45-405 FNGC but it may be a little small in diameter if your Marlin has a wide groove diameter. The nose shape and crimp groove location is fine for use in repeaters.