Designing your own wildcats

[30mm Vulcan Cannon]

Where does one start if you want to design your own wildcat cartridges?

Even though it's all talk right now, here are my cartridge names

224 Buzzsaw
6.5 Dart
270 Pilgrim
7mm Desert
300 Cupcake
8mm Aphelion
650 Centurion
500 Bulldozer (ramped up 500 S&W)

 

[MudRunner2005]

First, do a BUNCH of reading and studying about cartridge designs, powder capacities vs. bore diameters, what's already been done, what failed, what was revolutionary, what was hindered by the technology of its time, compare cartridge dimensions to other wildcats, common parent cartridges to wildcats, learn the difference in cartridge dimensions and chamber dimensions, tolerances, expansion and contraction of brass, the list goes on and on.

Also, get yourself a good cartridge design program.

 

[J E Custom]

First, do a BUNCH of reading and studying about cartridge designs, powder capacities vs. bore diameters, what's already been done, what failed, what was revolutionary, what was hindered by the technology of its time, compare cartridge dimensions to other wildcats, common parent cartridges to wildcats, learn the difference in cartridge dimensions and chamber dimensions, tolerances, expansion and contraction of brass, the list goes on and on.

Also, get yourself a good cartridge design program.

+1 Very good advice.

Wildcatting is not just changing something on a cartridge, It takes lots of though, lots of research and a good understanding of what each element does for the cartridge and what effect it has on a cartridge.

I would also buy PO Ackley's books and study them (He was one of the most prolific wildcatters)
and did lots of testing of different changes and there effect on cartridges.

It only takes one wrong thing to render the wildcat worthless, so take your time and seek advice
on anything you are not sure about.

Just my opinion

J E CUSTOM

 

[MudRunner2005]

+1 Very good advice.

Wildcatting is not just changing something on a cartridge, It takes lots of though, lots of research and a good understanding of what each element does for the cartridge and what effect it has on a cartridge.

I would also buy PO Ackley's books and study them (He was one of the most prolific wildcatters)
and did lots of testing of different changes and there effect on cartridges.

It only takes one wrong thing to render the wildcat worthless, so take your time and seek advice
on anything you are not sure about.

Just my opinion

J E CUSTOM

Definitely great advice.

I would like to add one thing... When you go back and read old books from PO Ackley, Roy Weatherby, and Townsend Whelen, always keep in mind, that these guy's opinions of their own wildcats are going to be different than what those same wildcats actually perform here in modern times. The reason is, bullet technology and powder technology and brass technology have come 10-fold from what they had back in the 40's, 50's and even up to the 70's and 80's. So, just because they were limited to certain powders and bullets back then, their wildcats might not have showed as significant of a difference as they do today with modern powders and bullets. Several examples would be the Ackley Improved versions of several cartridges. One prime example, Ackley himself stated that he didn't find the .30-06 AI to be worth the extra work, because the improvement was so small in his tests. Now, thanks to very specific powders for very specific applications, we know that this wildcat actually DOES show fairly significant improvement over a standard .30-06 Springfield.

So, what might have been deemed irrelevant back then due to technological constraints, might function like a hotrod today, with modern powders and technology. So, when wildcatted, don't always take things for face-value, until you've ran all the numbers. And if the numbers look like a sold enough improvement, then you bring it fruition.

 

[FEENIX]

For "me" the biggest factors for the endeavor is time and money; that's where "I" normally start (feasibility analysis), with goal, cost benefit/return on investment in mind.

lightbulb YMMV lightbulb

Good luck!

Hopefully Swamplord chimes in, he's got badazz wildcats. gun)

 

[30mm Vulcan Cannon]

All great advice here that I really needed! Thank y'all for the help!

 

[Rich Coyle]

Where does one start if you want to design your own wildcat cartridges?

Even though it's all talk right now, here are my cartridge names

224 Buzzsaw
6.5 Dart
270 Pilgrim
7mm Desert
300 Cupcake
8mm Aphelion
650 Centurion
500 Bulldozer (ramped up 500 S&W)

After reading what the others have posted I guess I must be lucky. I am up to about fifteen wildcats. At any rate one of my wildcats came as the result of thinking about bolt thrust. I decided the smallest case with a large enough case was the .220 Swift. The rim is slightly larger than the case. Since I like the Weatherby radii I decided to have that shoulder look. Ii was going to fire single shot so needed only enough neck to hold the bullet in the case. This would limit the amount of bolt thrust. The previous one was on a .378 Wea case shortened to 2 1/4" so there was lots of bolt thrust.

I purchased a Savage heavy 26" barrel Swift and had my reamer run into it before ever firing it. The resulting case holds 17% more than a standard Swift. Its favorite load pushed a 55 Nosler of Hornady at 4,005 feet per second. If a three shot group was larger than 3/8" it was terrible.

A friend named it .220 Extremist "because you are nothing but an extremist."

 

[elkaholic]

All VERY good advice above! I would add that you need a specific goal in mind so that you have a starting point. Just about EVERY parent has been has been blown out, shortened, shoulder changed, necked up, necked down, etc., etc.! Unless you are willing to accept the fact that it is very difficult to improve anything over what has already been done, it is a waste of time and money. On the other hand, it is a lot of fun for those of us who like to tinker and a LOT of popular designs out there now started out as wildcats. Good luck with your venture!........Rich

 

[J E Custom]

All VERY good advice above! I would add that you need a specific goal in mind so that you have a starting point. Just about EVERY parent has been has been blown out, shortened, shoulder changed, necked up, necked down, etc., etc.! Unless you are willing to accept the fact that it is very difficult to improve anything over what has already been done, it is a waste of time and money. On the other hand, it is a lot of fun for those of us who like to tinker and a LOT of popular designs out there now started out as wildcats. Good luck with your venture!........Rich

+1 More good advice.

Years ago it was almost a necessity to wildcat a cartridge if you wanted more than was offered.
Now with all the new powders and cartridges there is almost always something that will do what you want without going to all the trouble and expense.

If you go slow and think about what you want and read as much as you can about case designs and there benefit you can come up with your own design but again chances are that someone has already done it they just gave it another name.

I would look at what you want to do with it first. then decide what weight bullet is needed to obtain the optimum velocity. then decide how much powder capacity is needed to achieve safe pressure levels. Pressing pressures over the limit of any cartridge to obtain desired velocities will only bring grief. so go with a cartridge that will be at 90 to 95% capacity at maximum pressure and you will have wiggle room to get the best performance from it.

Body taper and shoulder angle will normally take care of most needs, but freebore, throat and lead
will also have an impact on how forgiving a cartridge is to different loads. DON"T GET TRICKY In these areas unless you totally understand there pitfalls.

Just my advice, Have fun

J E CUSTOM

 

[IdahoCTD]

Most everything I play with now is because of brass. I've built 29 wildcats (that's all I can remember anyway) and have 2 more in the works. The 2 in the works are a 6.5x68 Imp and a 7-338 Norma Imp. I have 160 rounds of RWS cases for the 6.5x68 Imp, which should last a lifetime as tough as RWS cases are, and I have about 1200 Lapua made 423 Dakota cases to use for the 7-338 Norma Imp and my 30-338 Norma Imp's. I like the Norma Imp. cases because it gives you as good or better than Ultra Mag performance in a 2.5" case length which leaves plenty of room to seat bullets long and fit in a standard magazine length. I'm building the 6.5x68 Imp to run just a hair faster then my 6.5-300wm's and to do away with the belt. I run RWS brass in my 6.5-300wm's too but the lack of sizing in front of the belt is a PITA so I'm trying something different.

Like Rich said above:

You really need a goal for what your trying to accomplish. If you don't have that it's a lot of time and money flushed.

There are tons of people that can help with the design if you ask.

 

[FEENIX]

Like Rich said above:

You really need a goal for what your trying to accomplish. If you don't have that it's a lot of time and money flushed.

I agree and that's why I responded ...

For "me" the biggest factors for the endeavor is time and money; that's where "I" normally start (feasibility analysis), with goal, cost benefit/return on investment in mind.

 

[J E Custom]

Something to think about.

There are many reasons to wildcat a cartridge. some wildcat just to have something that no one else has. Some want to try and improve the ballistics of the parent case. others are looking for something/performance that currently does not exist.(It does not have to be faster, it can fall in between existing cartridge performance and better fill a need.

Sometimes people build a wildcat because of component availability. and the tinkering person just wants to know what those changes will do. and some designs will "Improve" the brass life.

I am not as prolific as some and have only designed 5 to date for several reasons, Money and need.
In the process of working up a design I found other wildcats that were nearly identical so it was abandoned or bought. They have all exceeded my expectations.

I would also be careful when naming a wildcat, because it is important to give the wildcat a proper name so along with the performance comes respect for the round. Example ; 577 lollypop was one of the strangest I ever heard. When ask how he named it he said "Its a big sucker".

So if you take the time to build it, give it a good name.

J E CUSTOM

 

[FEENIX]

I would also be careful when naming a wildcat, because it is important to give the wildcat a proper name so along with the performance comes respect for the round. Example ; 577 lollypop was one of the strangest I ever heard. When ask how he named it he said "Its a big sucker".

So if you take the time to build it, give it a good name.

J E CUSTOM

LL, that's a good one.

 

[Mikecr]

IMO, it all begins with a bullet. You build the entire system around it.
As for wildcat naming, I feel the best standard is to simply name it what it is. 6x47, 25br, 6.5saum, 26wssm imp, 22-243AI, etc. The boo-boos and super-duper magnum this & that are pretty hard for the shooting community to accept as credible,, so they go unaccepted & fade away.