RBHarter
West Central AR
Got to think about the 410 as a 45 Colts loaded with a 260 gr WC.
A fellow ran data for a 350 gr up to 20,000 psi . 19 gr of h322 ,the start load so 2.0 off the max an capacity no compression max load , that in a 16" barrel ran right through 1200 fps . That puts a 3/4 oz load well within the limits of a 2" much less a 2.5 or 3" ,.410 and capable of 13-1400 fps in a 24-28" barrel . Anything that can be done with a 2.5" 45-70 Trapdoor US SAAMI should be good to go . It will sling a 530 1100 fps , that's a full 1-3/16 oz ........then all you have to do is walk the line for the no blowby wad seal and the squash around the shot charge does . That's start loads of course down around 18kpsi .
A fellow ran data for a 350 gr up to 20,000 psi . 19 gr of h322 ,the start load so 2.0 off the max an capacity no compression max load , that in a 16" barrel ran right through 1200 fps . That puts a 3/4 oz load well within the limits of a 2" much less a 2.5 or 3" ,.410 and capable of 13-1400 fps in a 24-28" barrel . Anything that can be done with a 2.5" 45-70 Trapdoor US SAAMI should be good to go . It will sling a 530 1100 fps , that's a full 1-3/16 oz ........then all you have to do is walk the line for the no blowby wad seal and the squash around the shot charge does . That's start loads of course down around 18kpsi .