Home Forums Hunting & Shooting Custom Rifles & Wildcats What's Really Best Way To Go?

Those who have the skill to create a wildcat have all the options. So for a hunting rifle that is a repeater, with a box magazine,
used in the USA and Canada, what are the best choices for the cartridge design?
(1) Can you who are actually creating wildcats, put together a list of traits that really ought to be included in a new cart.,
based on all that's been learned since about 1960 right up through today? And also, what traits would you say are absolutely
undesirable for a hunting cartridge?
(2) Is it true that 30-06 length carts., or longer even, without belts, with rims that have an equal diameter to the base of
the body, with shoulders of right around 20 degrees, REALLY DO feed more reliably than short action carts., (especially S/A
carts. that are fatter than a .308 Win) even if those S/A carts. have the rest of the above traits?
(3) I think it's great that RUGER engineered there RCMs to be able to reach higher speed quickly enough, to make the
use of shorter barrels viable. I read that it's a special blending of powders. Do you all agree that it's great benefit to be able
to use shorter barrels and get the same performance as from longer barrels with older carts. such as .338 Win Mag?
(4) What about the amount of taper the cart. has? I understand that having taper like we see in 300 H&H and 375 H&H Mags,
is rooted in the goal of reliable extraction in hot climates with the powders that were used scores of years ago. So is tapering
carts. simply not needed in new designs because of newer powders, or should we indeed continue to use a good amount of
taper with new designs? (We certainly are not seeing that!)
(5) Then there's the .350 Legend, that I guess headspaces on the case mouth, it having a straight wall design. What about that?
Thank you for sharing whatever information that you can! Nothing beats real experience!

I’ve loaded for wildcats but never designed one from the ground up. I may not be the expert you seek, but I’ll give it a try.

Most wildcats are born to meet a very specific need that no other cartridge meets. That's how the 223 Remington becomes the 25 Copperhead, the 300 WSM becomes the 9.3 BS, and the 30-06 becomes the 6mm-06. You can also use it to work within other very specific limitations, such as when a 30-06 with a pitted chamber becomes a 30-338. If you can’t find 8x57 cases, then turn your 8mm Mauser into an 8-06. If it’s illegal to have a rifle chambered for 7.62x54R, then convert it to 9.3x54R. And so on...

The need that you identify is so broad that a wildcat is probably not the answer. I’ll guess that you’re traveling to hunt since you mention two countries, so I’d steer clear of having your loading bench be your only ammo source. Your toughest requirement a box magazine. The AICS system solves for that neatly, so I’d look for factory rounds that work in their design and build your rifle out from there.

To address your specific points:

(1) I’d want enough power and accuracy for the game in question, plus a common bore diameter, short powder column, steep shoulder, and a common head diameter. I’m OK with belts and double-venturi shoulders, so the only undesirable traits I can think of are lots of body taper, being longer than the 30-06, a rimmed case, or an odd bore diameter. Dozens of existing cartridges would work, but the 308 Winchester and the 300 WSM rise to the top. If you have to use a wildcat, then the 308x1.5" or 35 WSM would work well.

(2) No idea, but I’d focus on magazine, feed ramp, and extractor designs at least as much as cartridge design.

(3) A lot of new cartridges are designed to perform in short barrels because the designers expect them to be used with suppressors. The fact that they often match older cartridges is a bonus. But short barrels are only nice if the rifle balances well, and not all carbines do.

(4) Yeah, you can get by with less taper these days. But you still need some.

(5) The 350 Legend was designed to a) be legal for hunting in specific states, and b) work in the AR-15 platform. If those laws change or the AR-15 goes away, then there's not much point in it, which goes back to my original point about wildcats being born to meet very specific needs.


Okie John

Thank you for your thorough answer!

You might read up on proprietary designs like Lazzeroni or Gary Reeders wildcats. PO Ackley did a lot of cartridge and action testing back in the day, much of it w/o sophisticated equipment to quantify his results, but interesting information can be gleaned anyway. There's lots of interesting information out there that can help you get your head wrapped around it. Honestly, I doubt there will ever be a need for any more wildcats, especially if you plan on traveling with your creation, but, what fun is shooting the same old same old right? The exception might be the desire to use a particular rifle for a particular caliber that it wasn't designed for. I've built wildcats on a Savage 99 action because I wanted to be able to utilize the rifle of my choosing to shoot the caliber of my choosing.

Whether factory or wildcat, the main thing is to have fun.

The sharper shoulder and reduced body taper are often desirable except once you get into dangerous game where smooth feeding and extraction are critical. That is one reason why the .375 H & H with its very generous body taper and sloping shoulder is preferred to other .375s.