All,

I am not a lever gun guy, but my brother is, and
posed this question to me, since I do a bunch of
hand loading, shooting, and shade tree
gunsmithing. So, I will post the question here,
in hopes of getting some good info.

He has a falling block Sharps(modern replica by
Uberti), in 45-70. A fellow lever gun guy told
him he could shoot 45-90 ammo in this gun, and
sure enough a 45-90 round drops right in. Is
this safe?

Thanks in advance for any info you may provide.

Squeeze

Safe or not, it ain't right. No way should a 45-90 drop into a 45-70 chamber. For that to happen, the freebore section (there usually isn't one) ahead of the 45-70 bullet would have to be as large as the case diameter of the front of the 45-90, or at least .478" to .480". Good luck trying to hit anything by making a lead slug come out of a 45-70 case and jump that gap. You need to take a chamber cast. It may be that it was mis-marked and it really is a 45-90. If it is supposed to be a 45-70 and the chamber is sloppy enough to accept a 45-90, about your only option is to go ahead and chamber ream out to 45-90 to take out the sloppy freebore section.

Someone will correct me if I am wrong on this one, but it is my understanding that a 45-70 Winchester case is 2.1" long, while a 45-90 Winchester case is 2.4" long. That being the case (pun intended) there is no way I would think a proper Winchester 45-90 case should fit into a correct .45-70 Winchester chamber.

Now, the Sharps 45-90 cases and the Winchester 45-90 cases are NOT the same, at least that is my understanding. I don't recall the exact difference in shapes, but Sharps suppossedly had at least two different shapes both wearing that moniker...at least one of which was a different cat than the Winchester round of the same name. No doubt someone on the Single Shot Forum here could tell you the precise difference(s).

Perhaps they meant to say that if you use a short 300 or 330 grain express bullet like the .45-90s did, you could then load the equivalent of 90 grains of black powder behind it and still fit both into a 45-70 case. That MIGHT BE possible, but I sure wouldn't recommend trying a 2.4" long case in a 2.1" chamber, even if I could force the lever closed on it.