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Discussion Starter · #1 ·
I've been playing with the idea of getting an Browning 1910 in 9mm kurtz and having it rechambered for the North American Arms .32 NAA. I been reading some impressive reviews of the round and I like the Browning but I've never been impress with the 9mm kurtz performance.

I'm looking for some feedback from the knowledgible posters on this forum on whether it's possible to start with and/or worth it for me to even consider it?
 

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It's going to co$t, but it might be fun. Seems like it would only requre a barrel and maybe a recoil spring change. Does Irv Stone still make weird barrels? - you might want to call Bar-Sto and see.

While I can appreciate the fun of doing something like this, this particular conversion doesn't appeal to me personally. I have not been that impressed with the accuracy reports I've been reading from the .32 NAA round (e.g., 4" groups at 20 feet) . . . while those may be the product of the gun platform, I have a hard time imagining NAA putting out a poorly made product. When that's added to the dubious nature of the performance benefits of this round . . . well, it's not for me.

But have fun with it if you decide to do it, and by all means post photos! :)
 
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Discussion Starter · #3 ·
I'm currently just trying to get some feedback on the con's of this possible project. The biggest of course is the $$$!

What I've seen of the reports, the test are out of a 2 1/2" barrel, so I don't expect groupings to be touching one another. I'm more concern with greater energy transfer, penatration, and wound cavity which I believe the 1 1/2" longer barrel will create.

The range at which I would use this weapon the 4" grouping under stress would be just fine if the trama that I believe it would inflict is correct?
 
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Discussion Starter · #4 ·
I don't know if I qualify as "knowledgeable," but I can give you some ideas to kick around.


Probably the biggie would be the barrel. Doubt very much if anybody is making any for this conversion. And if not, probably the cheapest way to go would be to get a M1910 in .32 ACP and have that re-chambered to .32 NAA. Now, chambering reamers for the .32 NAA are probably almost non-existent (outside of the NAA plant) and you would almost for sure have to come up with one for your gunsmith. Clymer is one of the best known makers, but there are others. Try Brownells, as they carry almost all gunsmithing tools and accessories on the market. If you have to buy one (or worse, have one made up) for your gunsmith, it will be $$$. I believe chambering reamers can be rented. Talk to your 'smith about this.

The other issue, and maybe the more critical one, is that the breech face of the slide and the extractor will have to be reworked for the larger-diameter case head of the .32 NAA. The alternative would be to obtain a .380 ACP slide, and I don't believe they are overly common or cheap. But it would probably be cheaper than the cost of modifying the .32 ACP slide, with a greater chance that it would work right.

Or start out with a .380 M1910 and pick up a good used .32 ACP barrel somewhere.


The recoil springing will likely be a cut-and-try thing. The stock spring might work fine, or you might have to go up or down in strength. www.gunsprings.com for this. Momentum of the bullet is the physical parameter of internal ballistics that determines recoil impulse. Momentum = bullet weight x bullet velocity. Compare the momentum of your .32 NAA loads to those of standard .380 ACP loads for a starting-point guide on springing. Be aware that if your M1910 is many decades old, its stock spring may very well be "tired."

Lastly, before jumping into this, you need to make sure that the pressure specs for the .32 NAA don't exceed those for which the FN/Browning M1910 was originally chambered. This would be 17,000 cup/21,500 psi for the .380 ACP cartridge. (The specs for the .32 ACP are a bit lower, 15,000 cup/20,500 psi, but I think if you adhere to the .380 specs you'll be safe enough.) I don't recall seeing any SAAMI pressure specs for the .32 NAA and I don't know even if SAAMI has any (not all calibers on the market have such, especially the more obscure ones), but I would start your inquiry with them. After that, try NAA or the ammo manufacturer (Cor-bon?), as they surely have some proprietary/manufacturer's working pressure specs on the cartridge. Whether they let those out as public info is another thing. Also, I would strongly gravitate to a post-war production M1910, as they probably have tougher steels than the pre-war ones, especially early pre-war.


The .32 NAA is quite closely based on a wildcat cartridge developed fairly recently (not long before the introduction of the .32 NAA cartridge). I forget the particulars (it seems that NAA slightly lengthened the .380 ACP case for their version, and case dimensions differ a bit), but the guy who developed the wildcat reworked and used a pre-war pocket auto for his experimentation. I believe it was a Savage pocket auto. The most recent edition of Cartridges of the World might list the wildcat cartridge. Or maybe the next edition might.

Do some Yahoo and Google searches with ".32" . You'll get a lot of .32 revolver references, but maybe some answers you need to know.



While I can appreciate the fun of doing something like this, this particular conversion doesn't appeal to me personally.: . . . . . the dubious nature of the performance benefits of this round . . . well, it's not for me.
Insofar as terminal ballistics issues, I'm strongly inclined to agree with this. Within the ballistic envelope that handgun cartridges operate, bigger is better --- even if velocity and "paper energy" is substantially less. (But if we all just spent money on what we absolutely needed, none of us would have very many gun-toys.)
 
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