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Discussion Starter #1
Just wondered if anybody knew how strong the Navy Arms 1873 Repro rifles are in 45LC.
I like the looks of them, and just wondered if anyone thought they would be adequate for short range hunting
(Deer and Black Bear). I would like to use some good hard cast bullets for hunting, but just don't know what kind of pressures these rifles will handle.
Any help is appreciated
Thanks, Mark.
 

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THE '73 WINCHESTERS HAVE PERHAPS THE WEAKEST ACTION DESIGN OF ANY RIFLE [ AND THIS IS ALSO TRUE FOR HENRY AND '66 REPOS ]. IT WAS PERFECTLY ADEQUATE FOR BLACK POWDER LOADS. BUT ABSOLUTELY MUST NOT BE PUSHED WITH MODERN LOADINGS AT ALL OR YOU'RE IN FOR A MOST UNPLEASANT SURPRISE. THE STANDARD 45COLT LOADS ARE OKAY AND DO PICK UP ENOUGH STEAM FROM THE LONGER BBL TO BE DEER KILLERS TO MODERATE RANGES.
TM
 

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Dear MDF,

An interesting question,  one that I've been curious about myself.

What Terry said is true, certainly of the original 1873 Winchester's.  The .44 W.C.F. (.44-40) blackpowder cartridge developed about 15,000 p.s.i. so that is about what the originals are rated for.

Today, the steel that is used in the modern day 1873's is much superior and stronger than the steel used in the originals, so much so, that  one of the calibers available for the 1873 Winchester reproductions made today, is the .357 Magnum which is a 35,000 + p.s.i. cartridge!

Having said that however, the .357 Magnum case is much smaller than the .45 Colt.  Theoretically, the .357 Magnum case has a total chamber wall internal case area of 1.436" (.357x3.1417x1.28).  The .45 Colt has a chamber wall internal case area of 1.818" (.452x3.1417x1.28).  

So, theoretically speaking, the .45 Colt has 26.6% more chamber wall internal case area so the .357 Magnum pressure of 35,000 p.s.i. would have to be reduced by 26.6% or a 9,310 p.s.i reduction. Call it  10,000 p.s.i. to be safe.

This means that the .45 Colt at 25,000 p.s.i. puts the same total pressure against the chamber wall  that the .357 Magnum does at 35,000 p.s.i.

Okay, what about the thrust of the case head upon the bolt?  The 1873 Winchester has a toggle link action which is inherently weak. Let’s see how the pressure against the bottom of the interior of the cases compare. The bottom of a .357 magnum case measures .320” internal  diameter . At 35,000 p.s.i. chamber pressure, there is  2,815 .p.s.i. against the base of the case.  The .45 Colt has a .430” internal case diameter at the bottom.  At 25,000 p.s.i. there is  3,630 p.s.i. against the base of the case.  Using this criteria,  the .45 Colt pressure would need to be lowered to  19,380 p.s.i. to achieve the same total pressure at the case head as the .357 Magnum, or 2,814 p.s.i.

However, P.O. Ackley proved that the pressure against the chamber walls was sufficient enough to hold the cartridge case in place with little support from the bolt resting against the case head. This is because the total pressure against the case wall is much greater than that against the base of the cartridge as we can see by examining the above data.

What does all this mean?  Yes, the .45 Colt, and for that matter, the .44-40 can be safely loaded to higher pressures in a current production 1873 Winchester  than in the original 1873’s,  but one is on his own if he decides to experiment in this endeavor.  

Perhaps the folks that currently produce these rifles, can shed some light on this subject?

Sincerely,
John    
 

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John,

Sharp posting, very sharp. This is the kind of information the Beartooth Board is used to seeing.

I too had concerns about the repro '73s, not that I would own one for a number of reasons. I agree that it would be best to limit the handloads to standard pressures just to be on the safe side. If nothing else it will promote firearm longevity.
 

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Discussion Starter #5
Thanks for the reply guys. I guess I will probably stick to a Marlin Cowboy, especially since the price is more reasonable. The 1873 deluxe is really nice looking, but the Marlin will serve me better for hunting.
Thanks again,
Mark.
 
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