Fctory solids for the .458 Win Mag were 510gr., I seem to recall and the softs were 500gr. Yes - a good 480gr. would easily have made the grade for speed, indeed, today, would probably make 2,240fps, if a person thought that was necessary, that is.

The .450 Watts wildcat using the full length .375H&H case was identical to the very much newer .450 Lott in every way, except the Lott has a gentle sloping entry to the leade of the chamber, instead of a sharp corner and 45 degree angle. Thus when shooting short rounds, such as the .458 Win Mag. in the longer chamber, the 'corner' doesn't scrape off jacket material as it tries to enter the throat, weakening the jacket and damaging accurcy. The sloping angle more gently guides the rounded ogive of the bullets into the throat. That is the only difference between the Lott of 1980's and the .450 Watt's of the 1950's.

Back in the late or early 1960's, Winchester chambered up a few M70 magnums in .450 Watts. I had the pleasure of shooting one of them in 1973, factory marked .450 Watts by Winchester. 3 shots split the stock, which turned out to be poorly glass bedded. We were shotoing 600gr. Barnes with a compressed load of whatever powder Les' friend had put in them.