I`m pushing 243 gn. hard cast with a gas seal at about 1,750, but I`m running them through a cusrom built gun. A Mouslin Nigant action with a .411 Douglus barrel. That is max. I can get with 2 1/2 in. 410 hulls because I blow the rims if I push them any faster. Without a rifled barrel, or at least a rifled choke tube you won`t gain much due to lack of accuracy. If you looking for a quick fix that will give you a big jump load 65 gn. of a Black powder substitute in one of your 410 case and push in a .410 pistole bullet, the 170 gn. would be the one I would try first. Make sure your barrel is bored to at least .4095 befor you shoot any. The reason I recomand the black powder substitutes is because you can get enough presure to blow the case rim with it, and with smokeless powders I`m not getting good ignation in cold weather with the powders I`ve tried so far.