.41 Colt Auto

[TXTad]

I was randomly reading about the development of the 1911 after seeing this meme:


In reading about the 1911, I read about Colt working on a .41 auto cartridge until they realized the army was only going to accept a .45 after their screw-up with the .38. Searching for that brought me to this an old thread here: https://www.thehighroad.org/index.php?threads/browning-colt-prototype-41-caliber-cartridge.657289/

This got me more interested in the .41 Auto, and I eventually found this, and figured there may be a few folks here who are still interested: https://forum.cartridgecollectors.org/t/41-colt-automatic-cartridge/34189

It looks pretty close to 10mm proportions, but who knows what pressure it was operating at. If I were going to guess, I would expect somewhere between .38 ACP and .38 Super, so 26,500 psi to 36,500 psi. Sounds like .40 S&W like performance?

 

[TXTad]

I just edited the original post to include the correct URL for the old High Road post.

 

[loadedround]

You're not talking about the 10 MM Auto cartridge are you? Bullet diameter is .401''.

 

[.455_Hunter]

You're not talking about the 10 MM Auto cartridge are you? Bullet diameter is .401''.

Why would he be talking about a round developed 75 years after the one under discussion?

 

[bigpower491]

Interesting. But IIRC, the 41 Long had a diameter of .385, something along that lines.
I've got an old 41 Long, I believe it's a new Army made like 1895. Was me great grandfather's

 

[Jim Watson]

I doubt the 1903 .41 Auto chamber pressure was any greater than .38 Auto.

Colt tried again ca 1912 with the 9.8mm Colt in a reduced size version of the 1911.
I wonder how similar it is. 9.8mm = .3858", hmm.

FN produced the similar Grand Browning for a 9.65mm round.
9.65mm = .380" Bore diameter of allee samee 9.8 Colt at .386" bullet/groove diameter?

 

[Dave DeLaurant]

Interesting. But IIRC, the 41 Long had a diameter of .385, something along that lines.
I've got an old 41 Long, I believe it's a new Army made like 1895. Was me great grandfather's

The inside-lubed, hollow-based .41 LC bullet is indeed around .385-388, but the actual bore diameter of the revolver barrel is still sized for .401" bullets. It sounds like (and is!) a kludge, but Colt did it this way so you could also use the old outside-lubed, heeled base .401" bullets in a Long Colt revolver. I had a couple of .41 LC DA revolvers at one time, but that particular madness has passed.

 

[TXTad]

I doubt the 1903 .41 Auto chamber pressure was any greater than .38 Auto.

Colt tried again ca 1912 with the 9.8mm Colt in a reduced size version of the 1911.
I wonder how similar it is. 9.8mm = .3858", hmm.

FN produced the similar Grand Browning for a 9.65mm round.
9.65mm = .380" Bore diameter of allee samee 9.8 Colt at .386" bullet/groove diameter?

I agree on the pressure since they were still working with the "slide rule" 1903 guns.

Looking a little closer at the post on the Cartridge Collectors page, It seems like the case diameter was about the same as older .41 Colt revolver cartridge, so probably shooing a .380" bullet. I wish I could find some chamber and bore dimensions for the surviving 1903 pistol.

 

[Jim Watson]

From the Cartridge Collectors page

The UMC ledger says:
41 Automatic Colt

Mar. 1903. Commenced making samples for the Colt Company. Headless shell same length as the .38 Automatic. 6-1/2 gr. Walsrode Shotgun powder, metal case bullet 150 grains, .386 diameter, cartridge same length as 38 Automatic, diamer of head .417 to .422.

By crossing my eyes and squinting at load data, Walsrode Shotgun powder might be approximated by Winchester Super Field if you wanted to build a .41 Auto.

 

[bigpower491]

The inside-lubed, hollow-based .41 LC bullet is indeed around .385-388, but the actual bore diameter of the revolver barrel is still sized for .401" bullets. It sounds like (and is!) a kludge, but Colt did it this way so you could also use the old outside-lubed, heeled base .401" bullets in a Long Colt revolver. I had a couple of .41 LC DA revolvers at one time, but that particular madness has passed. 



View attachment 1126332

Cool, I did not know this. Thanks for sharing that Dave

 

[Monac]

I would have thought this was the gun and ammuntion under discussion: https://www.cartridgecollector.net/98mm-colt-automatic

If you Google 9.8mm colt automatic you find a lot a links about it. Here's one from Ian McCulloch's Forgotten Weapons YouTube channel: https://www.forgottenweapons.com/colts-prototype-scaled-down-model-1910-in-38-9-8mm/

Since this is less than .41 inch, have I got the wrong thing?

 

[Jim Watson]

Two different Colt projects
.41 Auto 1903
9.8mm 1910

Nomenclature is strange, not that there is no system, just that there are several and you have to know which is being spoken.

 

[TXTad]

I would have thought this was the gun and ammuntion under discussion: https://www.cartridgecollector.net/98mm-colt-automatic

If you Google 9.8mm colt automatic you find a lot a links about it. Here's one from Ian McCulloch's Forgotten Weapons YouTube channel: https://www.forgottenweapons.com/colts-prototype-scaled-down-model-1910-in-38-9-8mm/

Since this is less than .41 inch, have I got the wrong thing?

As @Jim Watson pointed out, that is a different but also interesting project. There was a lot happening in the early 20th century as militaries were updating as technology was changing.

 

[Jim Watson]

Since this is less than .41 inch, have I got the wrong thing?

Awright, it is a new day, I have late morning coffee to work with.

The original .41 Long Colt shot a heeled bullet the same as the OUTSIDE diameter of the case, at or near .41". The barrel had a matching groove diameter. So when the inside lubricated bullet of the inside diameter of the case was demonstrated superior by .45 Colt, .44 Russian, and .38 S&W, and smokeless powder was coming into use, the ammo companies wanted to get as close as they could in the older cartridge. An inside lubricated bullet in .41 brass came out at .386" and had to have a hollow base to expand into the .41 barrel.

I conclude that by the time there was an interest in an automatic larger than .38, the industry was accustomed to making .386" bullets and calling them .41s. The second time around, Colt dodged the issue by naming the 1910 round in French.

Trivia alert:
There was a third try with the .41 Colt Special revolver in the 1920s. Maybe fourth, cartridge collectors speak of a .41 S&W.

It is often said that you can put a .38-40 cylinder in a .41 Long Colt gun and shoot as well as with .41s, maybe better.
Sometimes. Sometimes not. Mike Venturino and Hank Williams Jr. looked into it and found that a barrel with a tiny little 41 stamp was likely of .408" - .410" groove diameter and not accurate with the .400" bullet of the .38-40. No .41 stamp, barrel likely of .401" groove, same as .38-40 and shot fine.

There was a gunsmith who would rechamber the .401 Herter to .38-40 after the supply of .401 ammo dried up.

A gunzine writer got USFA to make him a .41 LC SAA with .386" barrel and chamber throats. It shot solid base inside lubricated bullets of that diameter as well as any other "modern" revolver.

 

[Monac]

Thank you, Jim Watson, that was highly informative. I knew that 38-40 was a .40 and not a .38, but I did not know it was so close the inside-lubed version of the 41 Long Colt.

(I hope I have not started an argument about "there is no 41 LONG Colt", just 41 Colt!" similar to that concerning the 45 Colt. )

 

[Jim Watson]

Not exactly.
Outside lubed heel .41 bullets were at or near .41"
Some .41 barrels were nearly .41", others were .401" and good with .400" bullets from .38 WCF which were not close in diameter to .386" inside lubed .41s.

Since there was a .41 Short Colt, there should be no debate over .41 Long Colt.