I picked up a couple of boxes of Privi (PPU) 300-grain JSP. For factory ammunition, it appears to be among the highest performing factory stuff - on paper.

Is its advertised velocity accurate fired in 20-inch barrels?

Is its jacketed soft point bullet slow expanding enough for reliable penetration on elk?

You didn't mention which caliber, but I assume you are talking about 44 Mag. That bullet will have a great deal of muzzel energy and a horrendous recoil! I had a Browning 92 in 44 mag and found it to be the most punishing lever action I have ever fired. I shoot very hot 45-70's from a Marlin Guide Gun and find the 92 in 44 to be far more punishing!

As to down range ammo performance, 300 grain 44 mag is fine for shorter ranged, but with a Rainbow trajectory and blunt bullet you run low on Elk size performance in at most 100 yards. White Tail Deer hunters find 44 mag with the 200 or 240 grain loads to be effective out further.

Ivan

I have shot several hundred 300 grain 44 mags from my T/C Super 14" Contender and I enjoyed the damage they inflicted on fun targets like concrete blocks and tree stumps, but never enjoyed the damage they inflicted on my forearm and lower back!

Call me crazy but we’re talking about a handgun cartridge in a rifle. Punishing doesn’t come to mind in any of my .44 long guns. This includes Buffalo Bore, HSM, and Winchester bear loads.

In the early 1980s I had a marlin in 44 mag and I put a scope on that rifle. It was very humorous how many of my friends would want to shoot that rifle thinking it was a handgun cartridge and walk away with a scope ring around their eye, or even their eye bleeding

Yes, part of that had to do with relief and stock fit but my point is many people under estimate a handgun cartridge