Converting Hi-Power to 7.62x25mm?


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Justin
April 2, 2003, 03:23 AM
In another thread here, someone mentioned in passing that a custom conversion has been done on Browning Hi-Powers to 7.62x25mm. Does anyone have any more info?
If so, what are the pros and cons? Does the converted gun have to take special magazines?
How accurate is one of these?
And what does it cost?

I think that the CZ52 is a good pistol, but there are a lot of minor flaws that bring it down. Seems like you couldn't go wrong with a BHP-based pistol.

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Cthulhu
April 2, 2003, 03:57 AM
Converting a Hi-Power to 7.62x25mm is fairly straight forward and would simply require:
1. New Barrel in the appropriate caliber.
2. New Magazine
3. New Slide Assembly with an ejection port long enough to eject a live round and the required engineering changes to barrel geometry to get the aformentioned barrel to work.
4. New Frame to accomodate the longer magazine and mount said slide assembly.


Now if you would want to change the caliber to 7.63 Luger, that requires a new barrel and, depending on the feed lips, possibly a new magazine. There is little advantage to using the .30 Luger as it lacks the case capacity and power of the 7.62x25 and has nowwhere near the number of effective hollow point defensive loadings of 9mm.

Nightcrawler
April 2, 2003, 04:25 AM
I think the 7.62x25mm is too long to be converted from a 9x19mm pistol. That doesn't mean it's a bad idea; I'd love a brand new, modern-designed 7.62x25mm pistol and wish CZ would make one.

A better bet would be starting with a gun that fires a cartridge with the same or a long overall length as the 7.62x25mm round. 10mm comes to mind. That could probably be made to work with, at most, a new slide/barrel, new magazine, and some new springs, perhaps.

Pilot
April 2, 2003, 09:27 AM
A much easier conversion would be a .40 BHP to .357 Sig, if you just HAVE to have a bottle neck cartridge.

cratz2
April 2, 2003, 11:25 AM
I think it's a good idea, just maybe not with a 9mm donor pistol. I think a 38 Super would be much easier to convert.

I think it would be excellent if CZ or EAA would offer their compact 10mm sized pistol in 7.62x25. And 9x23 while they're at it.

I have a hankering for a 7x62x25 myself. Was going to buy a CZ52, then it got sold. Was going to buy a Norinco Tokarev copy, then it got sold as well. Sometimes it's bad to be a procrastinator. :p

RON in PA
April 2, 2003, 11:46 AM
It's much easier to buy a Tokarev. Yes, it's no HiPower but it's just as reliable as the HP when in its original caliber.

Handy
April 2, 2003, 02:56 PM
Are you sure the conversion wasn't to .30 Luger?

.30 Luger is a bottleneck cartridge that will feed in any 9mm design (9mm was derived from it).

7.62 x 25 is too darn long.

Wildalaska
April 2, 2003, 03:12 PM
Converting Hi-Power to 7.62x25mm?

Why?

WildcuriousAlaska

Porter Rockwell
April 2, 2003, 03:32 PM
OH NOoo!
Watch for the gun rags to pick the idea up, right, they already have.
Downsizing! It's the latest rage, why have a .44 Magnum that's got ammo available at every discount store when someone can sell you a 460 Rowland!
Ta-Ta!

Justin
April 2, 2003, 04:08 PM
Yeah, I'd love to see someone like CZ, EAA, or even Glock make a modern gun chambered in 7.62x25, but I figure that'll happen at about the same time you can buy an ice cream cone in Hell.

Seems that the next best possibility would be to have a custom job done. As for why, well, the 7.62 is a screamer of a round. Plinking targets at 100 yards with a pistol is a heckuva lot of fun (and something that far too many people think is impossible.)
As for Tok vs. 357 SIG, it seems that the fastest velocity (after a quick web search) is around 1400 fps, +-. The Tok is just getting started there. The round can be (so I'm told) safely loaded to get velocities nearing 1900 fps, and if you want to go even faster, there's always .223 Timbs...

I know that all of this can be done with the CZ52, but that pistol leaves a lot wanting. The entire paradigm of design behind it is based in Eastern bloc Cold War-era engineering. We've come quite a ways since then, most notably by coming up with the concepts of ergonomics and human engineering. High-profile sights, comfortable grips, and easy to use controls are in rather short supply on the CZ52 and TT33.

Plus, one would assume that modifying something like a BHP would result in higher mag capacity because you're going from a single stack to a double stack magazine.

It's the latest rage, why have a .44 Magnum that's got ammo available at every discount store when someone can sell you a 460 Rowland! Because with the advent of online shopping, I no longer need to go to a discount store for ammo, but can instead order up a case or three of whatever I want without even getting up from my chair.:) Besides, there's tons of surplus Tok out there, and man is that stuff ever cheap!

Pendragon
April 2, 2003, 04:11 PM
Wildalaska:

My understanding is that the round produces extremely high velocities and will pierce at least some soft body armour.

The idiot freak who killed a cop about a year ago used a CZ52 and this round to punch through his vest.

Not sure about the legalities as technically, AP pistol ammo is illegal...

Cthulhu
April 2, 2003, 04:16 PM
I would buy a strong, modern, ergonomic 7.62x25 handgun in a flat second, high capacity or not. Say an EAA Witness/ CZ-75/ 1911/P7 type in 7.62x25. But as most have mentioned, the cartridge is too long to simply adapt most modern pistols with replacement parts.
The OAL is .09" or more than the 9x23, 45 or 10mm, which is quite a big difference. There a documented Chinese conversions of 1911s to 7.62x25, but they are hackjobs and appear questionable at best.
If you want close to 1911 style dimensions and function with minimal reengineering, a redux of the 7.63 Mauser Star Mod A made with modern metals and heat treating would be the ticket. A new gun made up to fit the dimensions of the particular cartridge would be required to get truly "modern" design.


Before this degenerates into people extoling the superiority of .357 sig with light weight bullets at unspeakably high velocities compared to 7.62x25, please think back to the rudimentary physics concept of sectional density and its effects on penetration and the performance of bullets of similar construction.

Handy
April 2, 2003, 04:40 PM
Cthulhu's post makes me wonder if a .38 Super or 9x23 1911 couldn't be adapted to 7.62x25 without much fuss.

As long as the Tok round's overall length is close to that of the Super, it should feed okay. A cheap barrel could be make by boring and lining a .38 barrel with a .30 liner.

Use a buffer.

Anyone know if the OAL problem would work out?

Dr.Rob
April 2, 2003, 08:46 PM
BHP's in .30 Luger as pretty common, they just aren't imported here, and not to be confused with the Tokarev.

You'd need something like an AMT automag in 30 carbine as a starting platform, and likely end up with a really big gun rather than a sleek Tok. Why not just buy an unissued Polish Arsenal pistol and use that as the basis for a custom?

glockgazda
April 2, 2003, 11:28 PM
For straight forward conversion keep in mind few things: OAL of the cartridge is in the .45/10mm category; case head dia is the same as 9mm.

So you can either stick with Tok or CZ-52 for cheap plinking, or you can convert one of the 1911 designs. Prime candidates would be Springfield 1911 in 9mm or Para-Ord in 9mm; both have ramped bbls, breach face is cut for 9mm, and mags are available.

Dash Riprock
April 2, 2003, 11:37 PM
Makarov.com sells barrels to convert the CZ-52 from 7.62x25 to 9mm Largo, which is about the same size as a .38 Super. (They caution people not to fire .38 super or 9x23 in these barrels, because they are rather thin in the spot right in front of the chamber.) I believe that they simply lengthen the chambers of the 9x19 conversion barrels that Federal Arms sells.

I've seen plenty of 9 x19 barrels for the Tok, and they appear to be a bit thicker than the CZ barrels.The same conversion would probably work, but I'm not brave enough to try it myself.

Edited to add link http://makarov.com/cz52/index.html
You have to scroll about half way down the page to see the conversion barrels.

Destructo6
April 3, 2003, 12:02 AM
I believe I'm the one that mentioned this.

There was a poster on the old Makarov.com discussion boards that had a BHP converted to 7.62x25. This was 3 or more years ago, so I don't remember the poster's name. He seemed rather pleased with the converion and didn't mention any problems (nor price).

The post was memorable because he was excited about telling everyone and I was the only one who made a response.

Handy
April 3, 2003, 01:03 AM
Did he say how he got a cartridge .2" longer to fit in the mag and feed?

Grayrider
April 3, 2003, 09:02 AM
Gents,

IF the cartridge length is on par with 10mm or .38 Super, you could do this with a .38 Super Witness. All you would need is a barrel, as the .38 Super Witness will convert to 9mm with a barrel swap. You would need a barrel made custom for the large frame Witness slide, as the small frame 9mm slide is different. Given that you can swap Tokarev calibers from 9 to 7.62 with a barrel swap, I assume the case head dimensions are the same are close. Breach face would not be a problem then with the .38 Super Witness slide. 18 rounds in a mag I assume given the capacity of the .38 Super/9mm.

Of course getting the barrel might be the challenge. Maybe Bar-Sto or someone would do it for the right price.

GR

Jim Watson
April 3, 2003, 10:11 AM
OAL in the AA manual is 1.381" for 7.62x25, 1.280" for .38 Super, and 1.169" for 9mm P. There is just not room in the magazine or slide stroke to make the change.

There was one tinkerer on another board determined in his folly that he planned to get (somewhere) a blunter nose bullet, to be deep seated so as to fit the BHP magazine. He was going to ream out an available 7.65 barrel for the purpose. I have not seen him to post how it all worked out.

How about a 90 grain .380 bullet in 9mm or .38 Super? You can get a lot of velocity that way. I doubt it will come in for serious use where the sectional density would make much difference.

Cthulhu
April 4, 2003, 03:57 PM
Obviously I wasn't clear when I spoke about the OAL problem, Thanks to Jim for putting the specs down, I didn't have time to tabulate them when I posted previously. To have a difference in OAL of 0.1+ is quite significant. You may as well have it be 1.0" interms of converting a 10mm or .45 to 7.62x25. They convert (some) Tok's and CZ52s from 7.62x25 to 9mm, not the other way around. There are Tokarev varients built to be 9mm and they are not reverseable, due to mag well restrictions. Conversion just isn't feasible without a major re-engineering of the whole frame, negating any advantage in cost/time that might present. Full custom or a rehashed and metallurically improved Star A/Tokarev/CZ/C96 Mauser is about your only bet.

Sectional Density is very significant, when it comes to both solid (for heavy cover/body armor use) and conventional (JHP, JSP but non-fragmentary/exotic) bullets. Given the same velocities, the solid 9mm won't penetrate as well as the .30 cal bullet of the same construction and weight. You could decrease the disadvantage by making the bullet heavier, but then the bullet takes up more powder capacity, and the velocity decreases at the same pressures. JSP and JHP bullets of the same design, velocity and perform similarly if they have similar sectional density.
This is the reason that, at least with expanding bullets, the .50AE does not have a huge advantage on game compared to the .44 magnum, despite its seemingly large disparity in both bullet weight and paper energy. The 300 grn bullets in .50 give about the same sectional density as the 240grnrs in .44. Actual chrono'd velocity of factory loads are very close, hence the similar performance.

.308 caliber, 90 grn bullet SD = 0.136
.355 caliber, 90 grn bullet SD = 0.102

Destructo6
April 4, 2003, 05:10 PM
No Handy, he didn't. Like I said, it's been a few years, so the details are fuzzy at best. The only reason I responded to the guy's post is that he seemed so enthusiastic and was met with indifference.

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