45-120 -versatility ?

[ascast]

Hope this category is best. Got into a discussion about the 45-120. Question is can you use it as a 45-70? just seat bullets way out ?
It looks like the base dia. would be OK. Or maybe a 45-90? It is not a popular cartridge and brass is way too expensive.
so school me up
thanks

[beshears]

I would expect the bullet to bump to 50 cal in front of case then be squeezed back down to 45 cal at throat. I would expect terrible leading and no accuracy. Find a few cases and reload case at bench. Reprime, powder and wad and seat bullet by hand in the case.

[NSB]

I’m confused by your question. 45-120 brass is longer than 45-70, so it won’t fit a 45-70 chamber. Seating the bullets “way out” would only make the round longer yet. I have seen the question asked, “can I shoot 45-70 in a 45-90 or 45-120 gun” and the answer is yes, but the jump to the lands may affect accuracy. The 45-70, 45-90, and the 45-120 are basically the same case but in varying lengths. Using black powder requires a lot more powder than smokeless does to achieve even closely the same velocities so the cases are longer. A 45-70 chamber with smokeless powder will easily surpass the velocity of black powder in a 45-90 or 45-120 chamber with black powder.

[Don McDowell]

The 120 case is an inch and a half longer than the 45-70 case. The bullet would expand to chamber diameter and then be swaged back to bore/groove diameter, leading would be ferocious the velocity would likely be miserable, and accuracy most likely nonexistent. This isn't a 38/357 thing.If you have a 120 either spend the money for proper cases or have it rebarreled.