Developing a new wildcat - what do you need?

Status
Not open for further replies.
Ivy Mike

Ivy Mike

Member
Joined
Feb 29, 2004
Messages
2,769
Location
Las Vegas, NV
I have an idea for a wildcat that I want to try. The idea is to use an existing case that would fit into an existing semi-auto action with existing magazines. I already have my parent case chosen and bullets chosen. I need to know what equipment would be needed to start work on this.
The idea is to use the 5.45x39 case, cut the shoulder off for a rough length of 30mm. Then, neck down the case which is around 9.25mm where the shoulder was, to use a standard 7.9mm (.312) diameter bullet. Effectively creating a newer, more powerful 7.62 Tokarev or a .327 Magnum for an autoloading carbine.

So, what sort of equipment do you need to begin working on such a thing? I understand some of the process of reloading, but I'm not sure what you would do, after cutting the shoulder off the case, to size the case down to create the shoulder (where it would headspace) and fit the bullet.
 
You rough cut the case to a length longer than what you are going to want in the end first. Then you run it into a size die that has the diameter and shoulder you are wanting. After that you trim to final length.

Often the cases won't be perfectly formed the first time but will be blown out to fit the chamber upon the first firing. If you are doing a big jump in diameter, multiple steps with annealing might be needed.

Stuff like a short .30 cal from a .223 case is pretty easy though.

 
...and a barrel with that chamber. Or a lathe and a set of reamers ground to the specifications of your chamber, throat and leads. To use in a barrel.

A Pressure Trace II system would be nice to have, to know the actual pressure you’re running through the auto loading system.

A Lab Radar and perhaps Quick Loads would be helpful too.
 
Someone may have already tried it. Go to Pacific Tool & Die or Clymer Precision and look through their reamers selections. They have 100's of them most all variations and mixes. They can also make what ever you need. But you will need to be able to have a barrel made to fit your receiver and reamed to your chamber. Unless you have the tooling and skill set to do this, it's going to $$$.
 
Learn the ropes of forming and shooting wildcats from wildcats that have already been made.

Not to rain on your parade, but what you want to do has probably been already been done or something close has been done.

I reload and shoot a few wildcats and enjoy the process. I form cases and reload 38/45 Clerke, 22x6.8, 6x47 and 7mm International Rimmed. I also form cases for an obsolete round, 6.5x54 Kurz Mauser. It has made me decide that trying to invent a new "mouse trap" in ammunition is a daunting task and I really will not improve on what others have already done.

But one benefit of working with wildcats, I can form cases for a couple of cartridges that I shoot should factory cases become unavailable.
 
cfullgraf said:
Learn the ropes of forming and shooting wildcats from wildcats that have already been made.

Not to rain on your parade, but what you want to do has probably been already been done or something close has been done.

I reload and shoot a few wildcats and enjoy the process. I form cases and reload 38/45 Clerke, 22x6.8, 6x47 and 7mm International Rimmed. I also form cases for an obsolete round, 6.5x54 Kurz Mauser. It has made me decide that trying to invent a new "mouse trap" in ammunition is a daunting task and I really will not improve on what others have already done.

But one benefit of working with wildcats, I can form cases for a couple of cartridges that I shoot should factory cases become unavailable.
Click to expand...
No rain at all. In fact, a very similar cartridge exists. It's called the 7.5 FK. The trouble is that it remains proprietary and is only chambered in one gun which is ridiculously expensive. It's a screamer of a cartridge at 2000fps and 800+ ft-lbs. Hence the reason I chose the 5.45x39 as my parent cartridge. It's a little smaller around than the FK and would likely perform a little more sedately but it requires no new tooling. It's still short enough to fit in a large pistol (OAL would be shorter than the 5.7x28) and by using .312 caliber bullets, I have access to a range of pistol bullets or rifle bullets. Also, I even have a barrel I can use in the form of an old Mosin Nagant basket case.

I am guessing that the resulting cartridge could be chambered in any of the popular PCCs as it would still be tame enough for use in a blowback firearm with the appropriate springs and buffers. For a pistol, it would obviously have to be locked breech although I don't really care if someone else wants to make up a pistol for it.
 
Your mixing oil and water for at least a little chunk of this. I do like the idea, but you said semiauto carbine and .312 bullets. The 32 pistol bullets are generally too soft for carbine speeds. That case would be relatively small for dropping to .308 for common rifle bullets that would mate up a bit better. Something to consider as an inbetween would be .311 bullets intended for the majority of communist 7.62 platforms. Barrels and blanks are also a lot more plentiful. They are less common for loading purposes, but aren’t impossible to find, and if you really got into a pinch you could pull down bullets from cheap x39 ammo.

And you might also want to look at 32 French pistol rounds. They are anemic compared to what you describe, but likely not terribly far off.
 
WestKentucky said:
Your mixing oil and water for at least a little chunk of this. I do like the idea, but you said semiauto carbine and .312 bullets. The 32 pistol bullets are generally too soft for carbine speeds. That case would be relatively small for dropping to .308 for common rifle bullets that would mate up a bit better. Something to consider as an inbetween would be .311 bullets intended for the majority of communist 7.62 platforms. Barrels and blanks are also a lot more plentiful. They are less common for loading purposes, but aren’t impossible to find, and if you really got into a pinch you could pull down bullets from cheap x39 ammo.

And you might also want to look at 32 French pistol rounds. They are anemic compared to what you describe, but likely not terribly far off.
Click to expand...
I think ripping apart .32 French Long would really upset Gun Jesus.

I might have to do the initial testing and the like with FMJ ammo only. But when you say too soft, is that something that could be overcome with different bullet composition or do I need to look more at rifle bullets? The velocity range I was thinking of is already fairly close to those achieved by hot .357 magnum ammo although those loads tend to be close to double the bullet weight I was thinking of (~100gr) But .327 Mag is already clocking in at 1500-1600fps+ on a regular basis.
I was trying to avoid going to any communist platforms because of things like bullet selection. While the 5.45 case is a Russian round, the base and rim diameters are close enough to 9mm Para that it wouldn't matter in most guns.

I pictured a CZ Scorpion Evo in this round instead of 9mm. I chose that because you wouldn't really have to change the bolt. 5.45 will fit into most bolt faces and extractors used for 9x19 without a lot of work. The extractors might need to be larger to get a solid grip on the 5.45 but that's a simple change. The length would require some more space in the action but the OAL of this wildcat cartridge is already going to be near 5.7x28 so you're not talking crazy long stuff. Depending on the platform, that might not make any difference at all. In fact, something like a Ruger PC Carbine could be a great option because it has space inside and is built as a take-down carbine, meaning the chamber can take a longer cartridge without changing the internal geometry of the action too much.
 
I have been toying with the same idea but never got the time to do any real research or planning on it. My idea was to try and finish with a straight wall cartrige to take advantage of more capacity in the same size pistol compared to 9mm. I was thinking of using a 30 carbine as the parent but that was as far as I got. Good luck and kudos for getting farther than I did.
 
somethingbenign said:
I have been toying with the same idea but never got the time to do any real research or planning on it. My idea was to try and finish with a straight wall cartrige to take advantage of more capacity in the same size pistol compared to 9mm. I was thinking of using a 30 carbine as the parent but that was as far as I got. Good luck and kudos for getting farther than I did.
Click to expand...
It's funny you mention .30 carbine since that's almost what I'd be doing if I go through with this. A slight taper, and a really stubby bottleneck. I'd basically be making a .32 carbine short mag.
Maybe Winchester will buy it from me. :D
 
So the answer would be

1. Press
2. Dies, shell holder, crimping die, etc.
3. Scale for powder
4. Saw for cutting the case and trimming.
5. New bullets, powder, primers etc.

Question though. Do you have to deprime a case if it's new? For example, if I had new 5.45x39, pulled the bullets and dumped the powder, can I leave the primers in place seeing as most are Berdan primers?
 
adcoch1 said:
Isn't 5.45 and 7.62x39, 6.5 grendel, 6mmArc, etc. all the same head size? Pretty sure it is. If so, get some Starline grendel basic brass and form away...
https://www.starlinebrass.com/grendel-basic
Click to expand...
5.45 is smaller. I chose it specifically because it looked to be a good solution for a higher pressure, more powerful round that would fit into a 9mm bolt face without much need for modification. 5.45 is 10mm in diameter at the case head. 9x19 is just a few hundreths of a mm smaller. The rim on the 5.45 is also slightly thicker.
 
Handloaders Manual of Cartridge Conversions is worth a look as are the books on wildcats (sorry, don't recall their titles now). Good to learn from others as well as confirm that you're not doing something which has been done, or is known to be a bad idea for some reason.

How much can you safely increase the pressure over a Tok round in a handgun? Well worth it to look into limitations like that. May be worth it to have a Contender or Encore barrel cut first for ammo testing before you get into a semi platform and the issues you may run into there.

Desired COAL and what it can fit into?

I have pondered many conversions over the years but often ran into a wall or found out it had been done. Just trying to save you time up front rather than go down the road to find out you're the guy who necked 300BLK down to 5.56 :)
 
Ohen Cepel said:
Handloaders Manual of Cartridge Conversions is worth a look as are the books on wildcats (sorry, don't recall their titles now). Good to learn from others as well as confirm that you're not doing something which has been done, or is known to be a bad idea for some reason.

How much can you safely increase the pressure over a Tok round in a handgun? Well worth it to look into limitations like that. May be worth it to have a Contender or Encore barrel cut first for ammo testing before you get into a semi platform and the issues you may run into there.

Desired COAL and what it can fit into?

I have pondered many conversions over the years but often ran into a wall or found out it had been done. Just trying to save you time up front rather than go down the road to find out you're the guy who necked 300BLK down to 5.56 :)
Click to expand...

Tokarevs are loaded to roughly the same pressure as 9mm NATO. Lower than you find in 10mm and .357 Sig. Considerably less than 5.7x28 You probably wouldn't want to load for much more although you could. The big problem becomes recoil in a large pistol. That's why I intend the round for PCCs primarily. If you want to run it in some pistol, good luck.
The point at which I was going to cut the 5.45 case down leaves me with a 30mm long case before forming, so probably 27 or 28mm case length after trimming. Less than 40mm (1.5") in COAL.

and yeah, the cartridge I'm trying to roughly duplicate, already exists. It's called the 7.5 FK. But good luck getting it or finding anything to shoot it in, unless you want to spend a fortune on a CZ97 clone. I was hoping for heavy .327 Mag ballistics in an autoloading format.
 
What do you need to develop a new wildcat? Money. Lots of money.

First you will need to specify the chambering reamer and have it and at least a go gage made. You can do this with or without making an example cartridge but making one helps visualize your new cartridge, especially the throat length. You can use custom shoulder bumping dies to make the example cartridge. You will probably need another reamer slightly smaller in the body dimensions to make your resizing die. In your scenario you need to find a bolt action that has the right bolt size for the 5.45 case you have selected.

Then you use your lathe, chambering reamer and go gage to chamber a barrel and fit it to your action. Next use your lathe and the other reamer to make a resizing die.

Now you get to make up a powder charge for your new cartridge. You probably won't have access to pressure equipment so you will have to find something with the same bore diameter and similar case volume to start with. You get to strap your new rifle to an old tire on the shooting bench and touch it off with a string so you aren't holding it if it blows up.

If you don't already know exactly how to do all this or don't have a lathe you will have to hire someone to do it for you. Its not uncommon to realize later that you want to change something...

You will also face the tribulations of getting it to work in a semi auto.

I'm not trying to be negative or frustrate you, but now you know what the path looks like. Several posters have said there is likely a similar cartridge already available. They are correct.

Certain wildcats offer short cuts when the change is only necking up or down. For example a 22-243 or 20 practical is not too bad because you can use factory bushing resizing dies and the parent go gage. You should consider necking up a 6.8 SPC to 30 because it is very close to your goal and would have these advantages.
 
Jim Watson said:
You kind of glossed over "existing magazine" and action length.
I don't know of an existing gun suitable for a 7.7x30.
Click to expand...
7.9x28 but close enough.
If I do the development in an AK74 pattern rifle, the magazine already exists. It will require a spacer in the front of it to take up the extra space, but that's actually pretty simple to do.
The action length is long enough. CMMG already makes a magazine conversion for AR magazines to use 9mm, so the idea already exists.
And the reason I chose the caliber I did, is because there already exist barrels which are suitable for rechambering. I mentioned an old Mosin Nagant basket case I already own. The twist is already favorable (it's faster than it needs to be, but that's not a monumental issue) and there is plenty of meat left after cutting down the existing chamber and/or the option of boring and sleeving the chamber.
 
armarsh said:
What do you need to develop a new wildcat? Money. Lots of money.

First you will need to specify the chambering reamer and have it and at least a go gage made. You can do this with or without making an example cartridge but making one helps visualize your new cartridge, especially the throat length. You can use custom shoulder bumping dies to make the example cartridge. You will probably need another reamer slightly smaller in the body dimensions to make your resizing die. In your scenario you need to find a bolt action that has the right bolt size for the 5.45 case you have selected.

Then you use your lathe, chambering reamer and go gage to chamber a barrel and fit it to your action. Next use your lathe and the other reamer to make a resizing die.

Now you get to make up a powder charge for your new cartridge. You probably won't have access to pressure equipment so you will have to find something with the same bore diameter and similar case volume to start with. You get to strap your new rifle to an old tire on the shooting bench and touch it off with a string so you aren't holding it if it blows up.

If you don't already know exactly how to do all this or don't have a lathe you will have to hire someone to do it for you. Its not uncommon to realize later that you want to change something...

You will also face the tribulations of getting it to work in a semi auto.

I'm not trying to be negative or frustrate you, but now you know what the path looks like. Several posters have said there is likely a similar cartridge already available. They are correct.

Certain wildcats offer short cuts when the change is only necking up or down. For example a 22-243 or 20 practical is not too bad because you can use factory bushing resizing dies and the parent go gage. You should consider necking up a 6.8 SPC to 30 because it is very close to your goal and would have these advantages.
Click to expand...
so make a .300 BLK-Long?
300 black lung.
 
Previously you mentioned using a 9mm bolt face.

Why not use .223 instead of 5.45x39? Similar to the 22 TCM that converts get 9mm but used a cut down .223.

Probably more boring. But boring is predictable. And if it's your first time wildcatting, predictable is good.

I say that never making my own wildcat.

Still, my idea for a wildcat is a 6.8 spc blown out to 10mm for a straight wall 10mm long. Midway between 350 Legend and 450 Bushmaster. Just to keep the caliber wars going...
 
Jim Watson said:
OK.
For some reason I got the idea we were talking about a pistol. Mention of the FK and French rounds led me astray.

Let us know when you start bending metal.
Click to expand...
I kind of envisioned the round in PCCs so maybe thats where the idea came from. The intent was certainly to have it small enough to fit in a PCCs even though its about as long as you'd want to get in a pistol. We're talking Desert Eagle size grip frames.
 
Status
Not open for further replies.

Similar threads

3
  • Locked
45 ACP Bullet/30-06 Case Wildcat
Replies
3
Views
1K
Kosh75287
K
T
  • Locked
.223 Rem Wildcat?
Replies
14
Views
1K
oldpapps
oldpapps
WestKentucky
  • Locked
What wildcat?
Replies
3
Views
230
tightgroup tiger
tightgroup tiger
K
  • Locked
Your thoughts on wildcat.
2 3 4 5
Replies
106
Views
7K
DWFan
D
D
  • Locked
.429 Wildcat
Replies
23
Views
1K
TRX
TRX
Back
Top