The MagTech 2-7/16" shells should duplicate the 2,5" shells that the 1887 was constructed for pretty closely.
Back in the day the 2,5" all-brass shells would have been roll crimped too.

I have an early-production Norinco 1887 chambered in 12/70.  I use un-cut, un-crimped MagTech all-brass shells, but do not load them from the magazine; I put one in the chamber and one down on the cartridge lift.  I have done some smoothing of rough edges inside the receiver / chamber area, and this set-up has served me well for years in CAS-mainmatch.

I will have to do some more experimenting with paper or plastic shells in order to make it feed six shells from the magazine for Wild Bunch.

Slim, we'll be shooting at either AR500 steel or paper. Anything short of AP will be o.k.

Seeing as how deaconkc has the stove going for the stove going for the coffee and Coffinmaker has made this into a Brunch hand Russ tosses in a baked diner of meat loaf and baked mac&cheese.

Abilene,yes Sir they are Magtech, 2 7/16" long whereas the paper shells ,roll crimped and ready to fire are 2 1/4" in length.
Macon

What ammo do we need for the long range rifle?

Slim