yup switch bullets in any of them and the test could turn out just the opposite. Stick a 405 hard cast in the 4570 and drop to 1400 fps and it would probably still be penetrating. Three major penetration effectors in any gun are bullet used, sectional density and velocity. I went to a Linebaugh seminar years ago and entered the penetration contest with one of my favorite loads. It was a 44 mag bisley 5.5 in gun with a very hot load pushing a 340 lfngc cast out of 5050 ww/lino at 1200fps. It beat out about every gun there including my own 458 mag using ww 500 solids and a 458 lott shooting solids. Only thing that beat it was two different 475s one shooting a 440 hard cast and one shooting one of kelly shlepps solid brass punch bullets. We had a man there (and the names slips my old mind) that spent many years in Africa and did quite a bit of elephant culling and he said flat out that the best pentration hes gotten out of any gun rifle or handgun was with his 475. He too used hardcast but had recently switched to punch bullets. He told us an elephants skull was like honey comb and very hard to penetrate and the 475 was one of very few guns he would say that consistently did it. He also said he backed his loads off to 1200 fps because anymore then that and pentration suffered. Buddy and I have done many hours of penetration testing years ago and the first thing to throw out if you want real penetration is soft nosed bullets. The second thing you have to wrap your mind around is velocity is more of a hindrance then a help. It is exactly why that 4570 didn't do as well as the 500 and why that big slow slug penetrated so well. That said if it would have been switched out to a conventional slug like a Remington that is cast out of pure lead those rifles would have eaten it for lunch. What you have there is the ideal slug load going up against probably a couple of the worse rifle loads. Id gladly wager 500 bucks I could take a 44 mag or 45 colt with a 255 grain hard cast lfn at 1100 fps and woop any of those loads in a penetration test. loaded wit a 300 at the same velocity it wouldn't even be a contest.
A fun test, but meaningless for real world performance. A nice guy who can’t even use the correct terminology - “casing” instead of jacket, etc.
A better, but not definitive, test of loads for bear defense: https://www.fs.fed.us/pnw/pubs/pnw_gtr152.pdf
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