“Wildcatting” cartridges is nothing new. Ever since the invention of standard cartridges, people have been making non-standard cartridges out of them. The motivations for these home-brewed concoctions vary widely.
Everything from eking a little more performance — like the .30-06 Ackley Improved — to making an entirely new cartridge for a specific purpose, like the 6.5 Creedmoor, to matching the performance of a caliber made for one type of firearm to another, such as the .300 Blackout. Then, there are those that are made just because they can.
That final category is at least partly the reason for one of the newest intermediate calibers, tentatively dubbed the .25 SPC. Like me and a lot of other pig hunters I know, the good folks at Precision Rifle Ordinance in Carthage Mississippi have been long-time fans of the 6.8 SPC.
P.R.O. had a lot of trouble getting a 6.8 SPC subsonic load to cycle reliably in an AR-15 (I gave up on that project years ago). They suspected, however, that they could wring more velocity out of the round while still maintaining almost all for the weight by dropping down to the 117gr .257 bullet.
P.R.O. started with the 6.8 Special Purpose Cartridge case, a modified .25 Remington case. They necked it down to accept a .257 caliber round. They worked with both Hillbilly Brass out of Angleton, Texas for the brass and Dave Manson of Manson Precision as a technical advisor for the gauges and reamers.
The big technical challenge was, not surprisingly, getting just the right shoulder angle for the difference between the .277 and .257 rounds from the 6.8 SPC to the .25 SPC.
The cartridge was developed with the Hornady 117gr SST round in mind. Packed with a compressed charged of H322, that round should have a muzzle velocity of 2,800 fps.
The combination will deliver just over 2,000 ft-lbs of energy at the muzzle, remaining supersonic all the way out just past 800 yards, and still delivering 600 ft-lbs of energy at 600 yards.
That would make one heck of a varmint and antelope round, as well as being plenty of bullet for the white tail deer we have around here in Texas’s hill country.
A few of you may be putting together that this round is almost identical to the .257 Roberts of long-time fame, the cartridge that Jack O’Connor himself said was a more versatile cartridge than even the .243 Winchester. And this one will load in an AR platform rifle using 6.8SPC magazines.
The .25 SPC will be submitted for SAMMI approval later this month. I’m looking forward to it, and foresee a new 18-inch upper in my future.