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7.62 x 25 Project

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floydthecat View Drop Down
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    Posted: Mar 30 2022 at 8:49am
Many of us have likely seen videos of a 7.62 x 25 Tokarev carbine conversion. Me and fellow forum member 03man have launched ourselves on another conversion project. If we can make a carbine run on 9 x 19, I have no doubts that we can make one run on 7.62 x 25 Tok. It could be as simple as a barrel change. 7.62 x 25 has been safely loaded up to 1600fps from a pistol length barrel. Chronograph results from 9mm testing demonstrate that MV increases of 15 to 20 percent are realized when fired from 18-inch carbine barrels. MV from a properly loaded 7.62 Tok should approach 30-carbine velocities and maybe behave much like a carbine projectile.

Reasons, because we can I guess and it might afford the opportunity to load and fire boat tail projectiles. The Tok is a slightly longer round than the 9mm allowing a stiffer powder charge and shorter than a 7.62 x 33 allowing loading of the boat tail profile? 

Stay tuned and if you have any suggestions or warnings I have not considered, feel free to chime in.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote W5USMC Quote  Post ReplyReply Direct Link To This Post Posted: Mar 30 2022 at 10:04am
Sounds like a great project Roger. Looking forward to hearing how it turns out.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote GotSnlB28 Quote  Post ReplyReply Direct Link To This Post Posted: Mar 30 2022 at 12:58pm
+1, interesting project. It wasn't that long ago you could get that caliber in milsurp quite cheaply by the crate. Those days are gone I'm sure :(.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote floydthecat Quote  Post ReplyReply Direct Link To This Post Posted: Mar 30 2022 at 1:05pm
Yep, the stuff was everywhere. Some or a lot of it might have been Berdan primed or corrosive. Commercial runs between 9mm and 30-carbine price-wise, but I will be reloading anyway with the same components as 7.62 x 33. Cases can be formed from .223/5.56 brass with the Tok sizer die, no special die needed.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rebel92 Quote  Post ReplyReply Direct Link To This Post Posted: Mar 30 2022 at 1:55pm
And he is at it again LOL 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 35 Whelen Quote  Post ReplyReply Direct Link To This Post Posted: Mar 30 2022 at 10:37pm
  I recently bought a Chinese Tok for $199 as a pistol to throw under seat of my daily driver pickup. Bought 100 pieces of Starline brass and various bullets and set about reloading. 

   Here's my 2¢...

   *I've been loading various and sundry centerfire handgun and rifle cartridge for nigh on 40 years now. Nothing has approached the pain-in-the-butt factor of reloading like the 7.62x25, not even the 32-20, 38-40 or 44-40. It is very difficult to start seating a bullet straight and keep it straight with that short neck. Flaring the mouth cartridge to facilitate better alignment of the bullet almost consumes the entire neck of the cartridge.

  *The powders with which the best velocities are attained (AA#7, 2400 et al.) turn the firearm, at least my handgun, into a veritable flamethrower. The muzzle flash truly is something to behold. Might not be so bad in a carbine length barrel. 

  *Extreme spreads were on the whacky side.

  *The 7.62x25 case is significantly smaller than a .30 Carbine and operates at lower pressures (36,000 psi vs. 40,000 - 46,000 psi, depending on the source (CIP vs. SAAMI)) so I'm not sure a person can get all that close to .30 Carbine velocities.
  
  None of this is at all intended to discourage you, (I think it's a really neat idea) rather just some of the realities of the cartridge. I hope you'll sally forth with the project. If cheap surplus ammo were to ever become available again, it'd be a neat little carbine to have around!
  

 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote floydthecat Quote  Post ReplyReply Direct Link To This Post Posted: Mar 31 2022 at 5:25am
Information and comments are what I am looking for. All are welcome. 

I have everything I need to try this. The base and rim dimensions mimic the 9 x 19 and I already have a very successfully converted carbine to 9mm. The only thing required to take this leap is a barrel and I have one. I have done a little research and do understand the Tok might be troublesome to reload. I also know it can be reloaded. The trick might be the projectile choice. I have fired some seriously monster loads from the 9mm, as in 146-grain 350 Legend projectiles over strong charges of AA#7 without showing any signs of danger. The carbine actions were proofed at around 48,000 psi using a 150-grain slug at that. That oal would be too long for the 30-carbine to feed, but it won’t for the Tok oal. I don’t plan to throw a 150-grain slug in it first to see what happens, but I do plan to play with projectiles, which should help with the reloading issues using the stubby light-weight projectiles. Spec 110-grain carbine projectiles are loaded in Tok and I have some published loading data for that.

There is going to be a bit of freebore in this chamber, which will allow the loading of longer projectiles. It remains to be seen how this will affect function and accuracy. I am 100% certain that I can make it cycle…..we’ll see what happens after that.

Developing a 9mm conversion was a somewhat long, arduous and at times aggravating project. Even giving-up at points along the way. We learned a lot of things in the process. The road to get the carbine to cycle at lower pressures at the gas-port has been traveled and we know it can be done. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 35 Whelen Quote  Post ReplyReply Direct Link To This Post Posted: Mar 31 2022 at 5:30am
Here's a good video on loading the 7.62x25 from Handloader TV

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Post Options Post Options   Thanks (0) Thanks(0)   Quote floydthecat Quote  Post ReplyReply Direct Link To This Post Posted: Mar 31 2022 at 7:22am
I have viewed just about every video I can find and continue to do so. What I found interesting is that H110 and other rifle power loads for the Tok are out there. The carbine gas system prefers the slower burning rifle powders. The issue with the 9mm is case capacity. I could barely get enough 296 in the case to make the carbine function, but it would cycle on about 7-grains. Additional case capacity in the Tok will allow a stronger charge and likely burn much cleaner. You have to get the pressure at the gas port close to what a 30-carbine round produces and the better grades of 9mm accomplish that. I will start with some commercial Tok loadings and work my way up from that if necessary. The carbine chamber fully supports the brass and I have never seen any indication of even an attempt to rupture a case. I routinely run commercial +p+ loads thru the 9mm. Winchester service grade and the mil-spec M1152 meets that standard at a published velocity of about 1300fps from pistol length barrels and a tad over 1500fps chrono’d from a carbine barrel.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote floydthecat Quote  Post ReplyReply Direct Link To This Post Posted: Mar 31 2022 at 7:42am
Someone shoot me down, or comment on this method of judging strength. Power Factor is a measurement of felt recoil. The higher the PF the stronger the load. You can mathematically work this out by knowing the velocity and weight of the projectile. A 110-grain carbine projectile moving at a velocity of 1900fps renders a PF of 209. That’s a baseline for a standard load. Actually measuring chamber pressure is something most of us cannot do, but it seems reasonable to assume that one can use a PF calculation to somewhat measure ammo strength? Can one assume that as long as PF is kept at 209 or below a degree of safety is realized? It takes a PF of around 150 minimum to cycle the 9mm. I have never shot a load exceeding a PF of 175.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote floydthecat Quote  Post ReplyReply Direct Link To This Post Posted: Mar 31 2022 at 3:51pm
Loading the longer 110-grain projectiles goes easily and they follow the neck. These cases were formed with a set of Lee dies and the neck was not at all difficult to form. It will depend on the quality of the brass and .223 might be easier to work with. I did not have to ream the case mouth on these and after loading, neck diameter is .334-.335 right on spec. 223/5.56 brass is a slightly smaller diameter than the TOK, but I suppose it will fire-form to the chamber.

I have a supply of the 86-grain Mauser projectiles and will give them a try at my next session, but I am pleased with what I built so far.







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Post Options Post Options   Thanks (1) Thanks(1)   Quote floydthecat Quote  Post ReplyReply Direct Link To This Post Posted: Apr 08 2022 at 7:22pm
Here I am, way out in left field doing things only I care about 😁.

I have the Tok conversion up-n-running. Having been thru the process of making a 9mm run, making this leap was really not much of a leap, only a step. Currently hand loading for it due to the scarcity and price of 7.62 Tokarev.  Not as high as carbine ammo, but more than 9mm.

There is really not much to be gained by doing this, mostly because I had the stuff and the time. If 7.62 Tok was as abundant as it once was, it would be a more worthwhile to perform this conversion. Not much to it, a re-chambered barrel, modified bolt, gas piston and nut as well as one specific 9mm extractor. Accuracy as good as me at short ranges. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote GotSnlB28 Quote  Post ReplyReply Direct Link To This Post Posted: Apr 09 2022 at 7:52am
Somehow, I knew it wouldn't be long before you'd post it was working. Nice!
How did you go about re-chambering the barrel and what tools did you use? Did you use a new barrel or a used USGI?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 35 Whelen Quote  Post ReplyReply Direct Link To This Post Posted: Apr 09 2022 at 8:21am
Good job getting it up and running! I'm going to have to try my hand at making my own Tok brass.

 Did we discuss bullet diameter? I know the cartridge supposedly uses .312" bullets, but I have a half-dozen 85 gr. bullets I pulled from surplus 7.62x25 cartridges and I seem to recall them being .307" or so.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote floydthecat Quote  Post ReplyReply Direct Link To This Post Posted: Apr 09 2022 at 9:30am
7.62 x 25 bullet diameter can be a bit confusing and I do not pretend to know all about it. Some European pistol bores are .312 and some .308. One just about has to slug the bore on any import pistol to be sure. Most (if not all) modern commercially loaded ammo is .308. This conversion utilizes a 30-carbine barrel, which is of course .308. All the components for reloading the TOK are the same as the 30-carbine…..bullets, powder and primers.

The re-chambered carbine barrel will have quite a bit of freebore as the carbine case is 33 and the TOK is 25. Conversations concerning freebore are all over the place concerning it’s effects and some chambers have freebore by design. In this case, it does not appear to be a major issue. The short ranges I have shot so far indicates it patterns like my 30-calibers. Un-chambered carbine barrels are available, if one wishes to make the investment. So far, I am content with a re-chambered carbine barrel. 

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Post Options Post Options   Thanks (0) Thanks(0)   Quote floydthecat Quote  Post ReplyReply Direct Link To This Post Posted: Apr 09 2022 at 10:10am
I have loaded and fired both 30-Mauser and reformed .223 brass. I load the .223 brass a tad lighter due to reduced case capacity. They both run very well charged with H108 and W296 under 110-grain carbine and 93-grain FMJ projectiles. I have other powders and loads to play with for a while. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote floydthecat Quote  Post ReplyReply Direct Link To This Post Posted: Apr 11 2022 at 8:26am
Originally posted by GotSnlB28 GotSnlB28 wrote:

Somehow, I knew it wouldn't be long before you'd post it was working. Nice!
How did you go about re-chambering the barrel and what tools did you use? Did you use a new barrel or a used USGI?

Don’t think I ever responded to this, but I will now.

I used a SG barrel with an ME of 1.5, which had been abused by Bubba. Darn good barrel, but he had (for some reason) filled-off the makers mark. I used a 30-Mauser finish reamer, which is the same chamber as the 7.62 Tok. Not much out there concerning Tok head space and I just head spaced it based on my gut. I think .005-.006 is the reasonable target, but it’s difficult to measure on cases that head space on a shoulder. I used slack between the rear of the right bolt lug and the receiver recess as a judgement. In reality, it seems that head space can be rather liberal like the 30-carbine or 9mm. I shot for .010 based on the bolts I have. Reaming was fairly easy as all one is doing is removing the difference between the diameter of the 30-carbine and Tok case diameter. Head space can easily be adjusted by moving the position of the shoulder on the brass by adjusting the sizing die. Reaming an existing carbine chamber will result in a good bit of freebore since the carbine case is 33mm as compared to the Tok case of 25mm. This turns out to be a hidden blessing as you can leave the neck longer for better case retention. It does not appear to have a great affect on function or rough accuracy. I have not performed any serious accuracy testing yet.

I am loading at a level about 75% below a 30-carbine load. 13-grains of H108 is the Hodgdon spec for 30-carbine and it runs fine at 11-grains.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote floydthecat Quote  Post ReplyReply Direct Link To This Post Posted: Apr 16 2022 at 4:26am
I have no idea what Herbert Werle did to achieve a 7.62 TOK conversion, but if he got too complicated, it was not necessary. The only requirements are a barrel chambered for 7.62 x 25, open the face of a GI bolt to accept the cartridge base, possibly a little trick in the gas system, an extractor and some ammo. The rest is USGI spec, even the magazines. 

Accuracy with the 110-grain Extreme bullet is completely acceptable at pistol ranges and about as good as me and a 30-caliber carbine. Lighter projectiles not so much, but work with various weights and profiles will continue. Commercial ammo that cycles the action is available. S&B published velocities of 1650fps will deliver a MV approaching 1900fps from a carbine barrel. 

Ballistically it’s not going to be a bit better than a 7.62 x 33, but with the right projectile (maybe a spitzer) it will get closer. One often hears about the desire to shoot an alternate projectile, here’s your chance. 

Not gonna say much more here, but a few of you have indicated an interest. PM me if you’d like some additional technical information.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 03manV Quote  Post ReplyReply Direct Link To This Post Posted: Apr 19 2022 at 12:16pm
Nice work !
Since you did the grunt work, I'll rechamber a "surplus" plainfield takeoff and have a "M1 carbine" in the same caliber as my Russian TT33 and Semiauto PPS43.

Then if we are ever "invaded" by North Korea or the Russians I can use their ammo! ;)

I believe there is a Werle video on U-tube on his Tok conversion.
Don
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Post Options Post Options   Thanks (0) Thanks(0)   Quote floydthecat Quote  Post ReplyReply Direct Link To This Post Posted: Apr 19 2022 at 1:35pm
Originally posted by 03manV 03manV wrote:

Nice work !
Since you did the grunt work, I'll rechamber a "surplus" plainfield takeoff and have a "M1 carbine" in the same caliber as my Russian TT33 and Semiauto PPS43.

Then if we are ever "invaded" by North Korea or the Russians I can use their ammo! ;)

I believe there is a Werle video on U-tube on his Tok conversion.

My partner in crime!

03 is the machinist in our experimental adventures. I dream-up stuff for him to do and he fixes what I mess-up and makes it work.

I continue to work on loads, but have determined that the carbine will cycle on over-the-counter commercial ammo, which is still available. I prefer to avoid the communist-bloc stuff. Much of it is suspect corrosive and Berdan primed. I prefer Boxer to reuse the brass.
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