I am loading for a Remington Rollingblock Rifle custom built on an 1896 frame. I have come into a small quantity of 500gr cast lead bullets, but can not find a load for this heavy a bullet. Hodgdon has a load using H4198 for a 485 round of 28gr. I am currently loading 27gr of H4198 for a cast lead bullet of 405-410grs. This is a very heavy gun with a custom 32" barrel for target shooting. Would a starting load of 28grs be a safe point? Suggestions?