I use a couple of similar bullets in my Navy Arms repro. of a .451 Rigby target rifle which has a 1:24" twist. The first mould I used was a Lyman 457121PH which throws a bullet of about 480gns. I had a hankering for a nose-pour bullet so had one made that is quite similar to the Lyman but has a slightly longer bearing surface & shorter nose, & weighs about 10gns less. Both will shoot sub-2MOA groups at 100yds fired prone with a sling, with the NP mould being slightly more consistent. I use 65gns Goex 2Fg with a wonder wad between bullet & powder, & wipe between shots. Have not shot this rifle at any longer range than 100yds/meters, but feel it should do well with either of above bullets out to 600m, but 1000m might be stretching things a bit.
I size my bullets to just under bore size, in my case .452", & start them into the muzzle by hand, the rifle came with a starter but have not found a need for it. I also pan lube my bullets with SPG before sizing. Hope this helps.
