Reloading for Winchester 1873 44-40 Max Pressure

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The_Champ

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Just curious about a particular reloading issue I noticed for the Winchester 1873 in 44-40.

All of the reloading manuals I have are careful to specify that when reloading for older 44-40 rifle models, including Model 73's, and reproductions of these rifles, be careful to keep pressures low, around 13,000 psi, as the action (toggle action in the case of the 73) wasn't designed for higher pressure loads. Of note, higher pressure 44-40 ammo was introduced when the much stronger Model 92 came along.

However, modern reproductions of the model 73 are chambered in rounds like the 357 Mag, which might top out pressures at three times what the recommended 44-40 pressure numbers are.

What's up with that? Is this just the reloading manuals using an abundance of caution in their published loads?

EDIT: I should add, I'm not interested in making hot-rod rounds for my 44-40 Model 73, just found that its an odd discrepancy. My guess is it might have to do with original model 73's having lower quality metal not meant for smokeless pressures, and the reproductions are likely much stronger.
 
Part of it is the base area of the cartridge, if my math is even close, a 357 mag at 35,000 psi is exerting 3,850 lbs while a 44-40 at 13,000 psi is exerting 2,210 lbs or 57% as much. A 44-40 at 22,800 psi would be equivalent to a 357 mag as far as force on the action goes.

Apparently Unerti makes a 1873 in 44 Mag, so maybe the design is stronger than we tend to think
 
I've often pondered that old pressure vs area thing, and without an iron ring the calculations begin to give me a headache.

Thrust on the bolt is one part of it, but the other part is the thickness of the metal enclosing the cartridge. With 44-40 and 45 Colt, the hole is pretty big and chamber walls are a thinner than if the barrel was chambered in 357 Mag. Even if you compare 44-40 to a 44 Rem Mag, the chamber walls are thicker in a 44 Rem Mag.

An Uberti '73 in 357 mag can safely shoot regular magnum ammunition, but no +P. From that I deduce that 357 Mag is at the limit for the gun. I have 2 '73's and a '66, and because I use them for Cowboy and Wild Bunch shooting, none of my loads approach max.

Interestingly the 1866 is a very similar design except the action is made from brass, which is weaker than steel, and Uberti does not chamber it in 357 Mag, only in 38 Special, and again, no +P.

I was considering having the chamber on my '66 lengthened to 357 so I could use the same ammo that I shoot in my 357 hip guns. As I don't load my 357's to anything more than 38 Special pressures, I thought it would be OK. It is OK, and some '66 owners have had it done, but I decided against it. The possibility of chambering and firing a 357 Mag round in it was more than I was willing to live with. As it is a 357 Mag round will not chamber.

I believe the action is good for a bit more than black powder pressures, but I'm also pretty sure the higher pressure the load, the more wear and stretch will happen. The toggle link action and the minimally supported bolt with several inline contact points can best be described as a contraption. I like my '66 and '73's, and I think they are safe enough too shoot, but no way are they as strong as a '92. And sometimes a bone stock '92 became unglued with 44-40 rifle loads. Certainly the ones that were reworked to 44 Mag had issues and better metallurgy was needed to make them safe.

I'm satisfied with 13,000 PSI.

Winchester brought out a high velocity load, WHV, for the '92 which was at least 20,000 psi, and they did not recommend it at all for the '73. About 30,000 psi is max for the 44-40 in a new '92.

It does seem like the '73 is the Trap Door Springfield of lever guns.

O6isF6s.jpg


'66 on the bottom (Cimarron), '73 on top (Winchester, Miroku), and my son's '92 (Rossi) in the middle.

Nitro
 
sail32 said:
This site might help you.

https://sites.google.com/view/44winchester/contributors/john-kort/two-peas-in-a-pod-by-john-kort

Marlin makes a 1894 in .44 Magnum.
Click to expand...

At some point John Kort performed a test with the 73' toggle link and was successful to prove it stronger than people think, also proving the toggle link was not the "weak link" (no pun intended) for early smokeless powders. I forget where they posted the information but it was in one of the forums. He never advocated shooting higher pressure loads in the 73' and preferred his Marlin 1894CB.

However, I would like to touch on the pressures.

SAAMI shows max pressures for both CUP and PIS (Piezo) and reloading manuals can goof between the two.

SAAMI Pressures - https://sites.google.com/view/44winchester

SAAMI
13,000cup (copper unites of pressure)
11,000psi (Piezo)



C.I.P. - Commission internationale permanente pour l'épreuve des armes à feu portatives
15,954cip (Piezo)
15,000cup


See where it gets confusing? For those that use QuickLoad, the 44-40 is in CIP, not CUP or PIS(Piezo)

So, in most handloading manuals CUP is used for the 44-40 but some powder manufactures websites use psi so be careful.

It was reported that sometime between 1903 and 1945, Winchester's 44-40 "High Velocity" cartridges produced 22,000psi (more than likely CUP). SAAMI wasn't established until 1926 and the pressures (documentation) didn't get serious until 1960. Some early 1930's handloading manuals use "Breech Pressure" but do not specify psi or cup. If the 22,000 is indeed cup, then that would be approx. 18,000+ psi.

In my black powder tests, early replicated loads in original cases produced 14,000psi while the same loads in later cases produced 12,000psi and 9,000 to 10,000psi in modern Star Line cases.
 
Last edited:
RE#7 was found to safely fill the case like BP and not raise the pressures to unsafe levels in even the 73 action.It works like a damn in my original 92
 
nitro-express said:
An Uberti '73 in 357 mag can safely shoot regular magnum ammunition, but no +P. From that I deduce that 357 Mag is at the limit for the gun. I have 2 '73's and a '66, and because I use them for Cowboy and Wild Bunch shooting, none of my loads approach max.

Interestingly the 1866 is a very similar design except the action is made from brass, which is weaker than steel, and Uberti does not chamber it in 357 Mag, only in 38 Special, and again, no +P.
Click to expand...

Uberti also chambers the 1866 in 44-40 and 45 LC
 
The 44-40 case is thinner than a .44 mag or 45 Colt case. Keep this in mind.
Hot rodding the 44-40 in a 1873 will just wear it quicker.I doubt you will end up with a catastrophic failure or break of components but you will develop a headspace problem if you feed it a steady diet of hot loads.
I would not do it.
I have one in .45 Colt and feeding it with mid range loads.
 
Bryan Austin said:
At some point John Kort performed a test with the 73' toggle link and was successful to prove it stronger than people think, also proving the toggle link was not the "weak link" (no pun intended) for early smokeless powders. I forget where they posted the information but it was in one of the forums. He never advocated shooting higher pressure loads in the 73' and preferred his Marlin 1894CB.

However, I would like to touch on the pressures.

SAAMI shows max pressures for both CUP and PIS (Piezo) and reloading manuals can goof between the two.

SAAMI Pressures - https://sites.google.com/view/44winchester

SAAMI
13,000cup (copper unites of pressure)
11,000psi (Piezo)



C.I.P. - Commission internationale permanente pour l'épreuve des armes à feu portatives
15,954cip (Piezo)
15,000cup


See where it gets confusing? For those that use QuickLoad, the 44-40 is in CIP, not CUP or PIS(Piezo)

So, in most handloading manuals CUP is used for the 44-40 but some powder manufactures websites use psi so be careful.

It was reported that sometime between 1903 and 1945, Winchester's 44-40 "High Velocity" cartridges produced 22,000psi (more than likely CUP). SAAMI wasn't established until 1926 and the pressures (documentation) didn't get serious until 1960. Some early 1930's handloading manuals use "Breech Pressure" but do not specify psi or cup. If the 22,000 is indeed cup, then that would be approx. 18,000+ psi.

In my black powder tests, early replicated loads in original cases produced 14,000psi while the same loads in later cases produced 12,000psi and 9,000 to 10,000psi in modern Star Line cases.
Click to expand...

The box of broken or bent links & pins from other folks rifles I have in my shop very much disagree with his findings. The fact is that the newer 73 clones that are chambered for 357 mag will not blow up in your hands with hi pressure rounds, modern steels the frames & barrels are made from prevent that from happening but no mater what the toggles/pins are made of they are still delicate at the pin boss's...I have even seen pin boss's in the frames with oblong holes forming from excessive pressure.

The fact of metallurgy in firearms is that pressure damage is accumulator, you might fire 1 round of high pressure cartridge in your rifle and break a toggle or pin or you might fire 300 rounds before a problem shows itself but be rest assured that one will appear inevitably.

The poster that mentioned that the brass framed clones are a "weak link" is correct when trying to "hot-rod" them for hunting rather than cowboy'ing. I have had two of them in my shop (both 44-40 from the same couple) that the owners decided to use their cowboy match rifles for deer and made some loads that they thought would be "better for killing a deer"...all they both did was kill their rifles. they brought them to me complaining that both their guns "quit firing and must have broken firing pins". The firing pins were fine...the problem was the frames had stretched and the toggle pins had bent so the firing pins couldn't reach the primers, one had 41 thou headspace, the other 45 thou...they were both boat anchors.

Toggle rifles, both originals & clones will last for thousands of rounds if they continue to be treated as the 1873 era action that they are...treat them as a modern hot rod and your $1600 investment will have a short life.
 
I'm loading 24gr /RE#7 /220gr GC/Win or Starline brass in a 1892 getting .680" 3 shot groups at 50 yards.Decapped a few grouse with it last fall.Velocity unknown?
 
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