atkinson,
I know about sectional density but what about JPK's contention that the flat point shape of 450 grain North Forks creates an effect that lets them penetrate deeper than Kynoch-shaped 500 grain round noses which have better sectional density? In other posts, JPK has actually shot animals with North Forks to prove this, IIRC. Also, there have been some theoretical studies about this posted on various boards, though personally I trust the people who have used them better than the theoretical studies.
Irrespective of shape, the sectional density of the 450 is over 300 and I can get 2250 fps with no pressure problems. From what I have read, that should put my .458 easily into the DG range.
The 450 grain .458 bullet has slightly better sectional density than does the 300 grain .375, slightly lower velocity, and 50% more weight; also slightly less sectional density than the 400 grain .416. What's wrong with that?
The only problem is that North Fork went out of business. I only have 44 of these solids left. Fortunately, I have the load worked up and I keep very thorough notes. The North Forks shoot 1.0" lower than 450 grain TSXs in my rifle at 100 yards, so I don't even have to waste any confirming my zero. 44 might last many years.
It ain't a theory! 450gr North Frok flat nose solids at 2200fps far outpenetrate 500gr Woodleighs at 2145fps. This has been the case with every 450 shot vs every 500 shot. The issue of greater penetration is resolved, at least for me, but how much greater pentration? My measurements and experiments in elephants leads me to lean toward believing that its in the neighborhood of 40%. But so many North Forks exited that I don't have enough of a sample to be really comfortable with that assesment.
500grs, who post here and elsewhere has also done extensive test, more extensive than mine. He finds a lesser advantage, in the areas of 15% IIRC. But many of the test he tried were equal weight flat noses vs equal weight round noses at the same velocity. So it seems that the flat noses gain advantage through speed rather than mass. But I am unaware of any tests in real game or ballistic gell designed to smoke this out.
Does indicate why moving to 450gr solids in the 458wm results in such a phenominal increase in performance though. The fellow who turned me onto the 450 North Forks finds the same remarkable increase in performance in his 450NE No2, a rifle not limited by its cartridge case capacity - the 450NE No2 has an enourmous case thal ALWAYS requires a filler - but rather a rifle whose velocity is limited by the pressure it can withstand and also by how the two barrels were regulated (same issue regarding regulation for my 458wm DR too, which is why my 500's are limted to 2145fps and the 450's limited to 2200fps.))
From 500 Grains tests, I would be very confident shooting GS Custom flat nose mono bullets, btw.
On lighter weight non DG bullets, used for trajectory improvement. I am a fan of keep it simple stupid. One weight bullet for each rifle on safari. Then your selection is limited to soft or solid. Better a more arched trajectory than the wrong weight bullet up the spout or in the magazine. But I suppose you could keep the light weights "locked up" until all the DG for the trip is shot and then retire the heavies. Still I'd keep it simple.
And Indy, don't let Ray Atkinson fool you, he has been touting the 450gr North Fork cup points - not flat nose solids - for buff for years, so his line about 500's only is just argumentative bull.
JPK
