Recently I have been playing with some ideas for a 20 cal wildcat. I already have a 221 Fireball and really enjoy the velocity it generates without using a ton of powder. That really helps to keep barrel heat down in the gopher fields. I also have a 223 Rem which is great but burns considerably more powder without a lot more performance.
A friend has a 20 Vartarg which is the 221 Fireball necked down to 20 cal. And as well I keep hearing how much guys like their 204 Rugers. What I was after was something in between. I can't help but think the 204 Ruger must be a bit hard on throats shoving all that powder down the little 20 cal bore, not to mention more powder equals more heat. But at the same time I wanted something with a bit more velocity and range than the little 20 VT.
The obvious solution was to lengthen the Vartarg or shorten the Ruger. I suppose either way would work just as well. That led me to case dimensions of 20x40 which is a nice round number and roughly half way between the two parent cases. The obvious name for this cartridge is 200 SPEX.
From left: 221 Fireball, 20x40, 223 Rem.
Anyone who has either shortened or lengthened an existing case will immediately recognize that case taper is going to create a problem. If the wildcat is shorter than the parent then the back end of the chamber is going to end up smaller than that of the formed case. If the wildcat is longer than the parent then the back end of the chamber will end up bigger than the formed case. This is due to the taper inherent in the reamer.
So the solution is to go with a minimum body taper Improved configuration. The reamer I will use is a 20 Vartarg Improved which will be run in 5mm (~.200") deeper to form the 20x40 chamber without producing a sloppy fit at the back end of the case.
If I were to desire a non-improved version of the 20x40, a custom reamer would have to be designed to give the proper dimensions.
Loading dies are reasonably simple. A Forster Ultra Seater in 20 Vartarg will have its chamber sleeve reamed to the proper configuration and length. The sizing die is a bit more difficult and spendy but Redding will produce custom dies based on a pair of fired cases.
Initial cases for fire forming will be made by cutting down 223 Rem and then sizing in my 221 Fireball die with a .20 cal bushing installed. I did a couple last night and they are surprisingly easy to make.
A friend has a 20 Vartarg which is the 221 Fireball necked down to 20 cal. And as well I keep hearing how much guys like their 204 Rugers. What I was after was something in between. I can't help but think the 204 Ruger must be a bit hard on throats shoving all that powder down the little 20 cal bore, not to mention more powder equals more heat. But at the same time I wanted something with a bit more velocity and range than the little 20 VT.
The obvious solution was to lengthen the Vartarg or shorten the Ruger. I suppose either way would work just as well. That led me to case dimensions of 20x40 which is a nice round number and roughly half way between the two parent cases. The obvious name for this cartridge is 200 SPEX.
From left: 221 Fireball, 20x40, 223 Rem.
Anyone who has either shortened or lengthened an existing case will immediately recognize that case taper is going to create a problem. If the wildcat is shorter than the parent then the back end of the chamber is going to end up smaller than that of the formed case. If the wildcat is longer than the parent then the back end of the chamber will end up bigger than the formed case. This is due to the taper inherent in the reamer.
So the solution is to go with a minimum body taper Improved configuration. The reamer I will use is a 20 Vartarg Improved which will be run in 5mm (~.200") deeper to form the 20x40 chamber without producing a sloppy fit at the back end of the case.
If I were to desire a non-improved version of the 20x40, a custom reamer would have to be designed to give the proper dimensions.
Loading dies are reasonably simple. A Forster Ultra Seater in 20 Vartarg will have its chamber sleeve reamed to the proper configuration and length. The sizing die is a bit more difficult and spendy but Redding will produce custom dies based on a pair of fired cases.
Initial cases for fire forming will be made by cutting down 223 Rem and then sizing in my 221 Fireball die with a .20 cal bushing installed. I did a couple last night and they are surprisingly easy to make.
