that 200gr will work but if it was me i would get some 230gr xtp bullets in 451. they hold together alot better than the 200s. i have tried both of them in a 50 cal cva long rifle with a 1-66and they worked good, but i only got to try them out to about 50 yrds. they did shoot round holes through the paper so i reckon they were flying stright but the 200gr bullets come apart purtty easy if you hit shoulder so if you do use them make sure you get a good rib shot.in a 45 cal cva with the 1-66 iused a blue sabot and a 38 cal xtp anddone well also.my friend used this 45 long rifle one season and killed two does and a mid size buck using the 38 xtp ammo, i think he was using 70 grs of powder. he said both the does went down the hill into the creek bottom before they went down and the buck took a back shot and hit the ground flopping, only copper jacket fragments could be found in the bucks back or that is where the back bone was. the shots on the does were pass throughs butthey did make some good exit holes.