"Back to guns.....the 45 long Colt in a strong 1892 action...made of modern steel will contain the same pressures that the Winchester Big Bore action will contain and even a bit more....50,000 cup..easily. (My article on the new Legacy/Puma 454 carbine is posted on
www.gunblast.com(My article on the new Legacy/Puma 454 carbine is posted on
www.gunblast.com But I still feel that it is not designed in a way that it will take a long sustained use of the full pressure of the 454 loads at 60,000+ lbs. So don’t go there with even a modern Rossi, Browning, or Winchester 92. I have tested the new Legacy(Rossi) Puma in 454....there are changes in the little carbine, good changes...the most noticeable is what they have done to try and keep the loading tube from shearing the muzzle holding screw...and the change in how you load....much like lever 22RFs. I still think they are going to have problems...I hope not...it is a small packable rifle, that gives the bottom end power of a heavy loaded 45-70.
If Legacy truly has a 92 action that will take 454 full pressures over a sustained high number of rounds fired...like 10,000 of them...then they have made some changes to the steel and the design we don’t know about...in my tests now over one thousand heavy pressure commercial and in handloads, the 454 Legacy has performed wonderfully. I actually thought with full loads it wouldn’t sustain even that. But I’m now glad I can say I was wrong.!
Something has changed..I know a very late model, carbon steel built Browning/Winchester 92, will not take more than a few hundred rounds of 454 pressures before it gets a beginning case of bolt set back. My 1990s 45 Colt Rossi model ‘92 with 24 inch octagon barrel also didn’t do well at the 60,000 lb. Level of pressure. One Winchester was so bad, the mortises on the bolt itself had to be peened back in place, and the steel bolt blocks had to be given Mig Weld lines up the front of them, and ground and refitted to regain action tightness. In our case, I was reloading 45 long Colt cases to 60,000+cup. When a modern Rossi...a Christmas present from my children and wife three years ago, is loaded to a top end of 50,000 cup....no damage has occurred after thousands of rounds.
Because of the changes in today’s steels (since the discoveries during the 2nd WW, I would worry about any converted old 1892 Winchesters to 45 long Colt) modern Browning, Winchester, Legacy and Nave Arms, are made today from excellent steels and will take magnum pressures...Remember the first 357 magnum S&W rounds were rated at 47,000 psi. We tested original 1935 first run ammo in 357 revolvers last year and they gave well over 1500 fps from an S&W N-Frame 8 inch+ revolver...so the pressures had to be up there. The modern 92s no matter the caliber will easily take magnum handgun pressures. Certainly they take hot 44 magnum pressures without problems, so they will take the same in reloads with the 45 long Colt. I’m sure most know by now that friends John Taffin, Brian Pierce, Jim Wilson, Jim Taylor, myself and others have killed the big lie that 45 Colt brass is weaker than 44 magnum brass...or any other type. So 45 brass at these high pressures is not a problem.
So where are we.....? Modern 92s, factory chambered in 45 long Colt can take 50,000+ cup loads. But I wouldn’t trust custom rebuilt old 92 actions in 45 long Colt to be able to sustain those top pressures, unless I knew the date of the action, and it was at the very least well after the 1930s. Also I have found that some of the heavy loads I use daily in my Ruger S/As in long Colt, are too warm for the early 1980s Winchester 94 actions in 45 long Colt. I have blown extractors, loosened ejectors, on them. Now that is my warm loads in the Rugers. Most folks don’t load that high...and I can understand that.
So I would put the very upper limit on pressure in these fine model 94 Winchester and Marlin leveractions at 40,000+ cup"
http://leverguns.com/articles/paco/45coltlevergun.htm