Back in the 50s after WWII, there were a lot of military surplus guns on the market, domestic and foreign. The bolt action Mauser Model 98 was a favorite to convert into a sporting rifle but you had to be sure it was a good one. The Czech 33/40 small ring and VZ-24 were rated with the best. Some of the 98’s were heat-treated properly, some were not which could lead to a number of problems.
The US Springfield rifle was also used to convert to a sporting rifle, but it wasn’t as advanced as the 98 Mauser, and so people by and large tended to shy away from it. One series of the Springfield rifles were also heat treated too hard, to the point where they were brittle which could lead to a dangerous situation.
As people began to prefer to sporterise the European surplus rifle actions, and since the foreign military calibers were not as popular in the United States, we began to use and install different caliber barrels on the actions. This lead to the popularity of wildcat cartridges. These were home brew, calibers instead of calibers produced commercially. And the experimentation made for a period in time where it seemed that everyone was making their own rifles practically from the ground up, instead of just adding bells and whistles. On an almost monthly basis it seemed like new wildcat cartridges came out.
People like Parker Ackley were experimenting with different shape brass cases formed from standard calibers. Ackley theorized that a 40-degree shoulder would cause more of the powder to burn in the case instead of the barrel and the pressure curve would be shaped better for higher velocities. We learned that every bore has a maximum powder capacity. You can only burn just so much powder in a given bore diameter. In other words, the 300 Weatherby for example, is overbore. The case holds more powder than you can burn efficiently. This is evident when you shoot it in the dark and a large orange blossom appears at the muzzle. The extra powder only adds minimal amounts of additional velocities compared to say, the Ackley 30/06 Improved with its 40-degrees at the shoulder and straighter case, which is one of the best performing cartridges in its class.
The 270 Winchester (.27 bore) and 257 Ackley (.25 bore) have also been considered the best within their powder capacity, but I imagine there are others now.
Custom rifles were in vogue chambered for all sorts of wildcat calibers then.
People like Douglas Barrel in West Virginia also sold barrels with all sorts of custom chambers. If you sent Douglas a drawing of the shell you wanted, they would build a chambering reamer to build a barrel and supply you with that barrel – within reason I should add. Douglas would also install the barrel on your action.
The next step was to buy the brass to form your wildcat cartridge. You’d then “fire form” your wildcat brass and reload them according to the new size you’d made. To fire form your wildcat case you could put a little fast burning pistol powder like Unique in the case topping that off with a little flour and sealed with damp newspaper. No bullet at this point. You’d fire the “blank” cartridge in the custom chambered barreled action. The damp newspaper and flour then created enough pressure to expand the brass case out to your new wildcat cartridge dimensions, while a the same time not causing the brass case to burst.
Some people fire the standard round in a wildcat chamber but you no longer have a proper head space and you run the risk of the round exploding in the chamber if you don’t go through the steps I just described. Some Wildcats required a bit more work. The 22/250, for instance, required a forming die to shrink the 25 neck on the 22/250 down to .22.
At that time, custom gunsmiths abounded. There were all kinds of sources and accessories for custom guns. Like guns, reloading was more of an art then than a way of loading a lot of ammo fast. In those days we loaded rounds one at a time weighing each powder charge. Today, like computers, I Phones etc., reloading tools must be fast and are quantity driven.
I think we've lost something over the years, and painting your AR-15 in a new camo design doesn't make up the difference.
Searching for something new, todays manufacturers have gotten into the “wildcat” act with all the new calibers they are coming out with. Two wildcat cartridges that became extremely popular to a point they became standards with Winchester and Remington are the 35 Whelen and 22/250. Townsend Whelen expanded the neck on 30/06 cases to accept 35 caliber bullets. This round was called the “poor man's magnum.” It was to compete with the belted expensive 375 H&H magnum. Ackley went one step further with his version. He added a 40 degree shoulder and a straighter case.
These cases are still readily available even now, and represent the last vestige of the great wildcat era.
The young bull upon seeing a herd of cows said to the old bull, let’s run down and get one. Giving a little thought to the subject, the old bull said, let’s go down and get them all.