Rechambering .222 Remington to .224 Valkyrie

The .222 Remington barrel used in this project came into the picture as a take-off barrel with a well-established history of accuracy. With its 1:14 standard twist, this barrel would be used primarily with lighter bullets up to 60 grains maximum when chambered for the .224 Valkyrie cartridge. Another premium barrel was on order with a 1:7 twist which would undergo comparative testing from the benchrest and in longer range shooting.

These cartridges would later be pitted against two barrels chambered for the .22 PPC with similar barrel twists. The .22 PPC has established an excellent reputation for extreme accuracy whereas the .224 Valkyrie is designed to be a smaller caliber, longrange round primarily with heavier bullets in a faster twist barrel. 222 Remington to .224 Valkyrie chamber conversion. The Remington Model 700 stripped-down action chambered in .222 Remington, and a reamer and headspace gauge used to form the .224 Valkyrie chamber.

This Remington receiver has been converted to single shot with a loading ramp. Accurate measurement of both the .222 Remington and the .224 Valkyrie cartridges indicated that a chambering revision could be accomplished by cutting only 0.190" from 222 Remington to .224 Valkyrie, the barrel tenon was shortened to advance the chamber by 0.190" and enlarging existing chamber 0.056" at the shoulder and 0.238" at the base. Leade cleanup would be performed in the process. the barrel tenon.

The existing .222 Remington barrel was absent about three threads at the beveled, chambered end anyway, and was fully threaded beneath the recoil lug leaving a near fully threaded barrel shank to work with. Based on these findings, systems were all go.

222 Remington to .224 Valkyrie. Note the marked bevel at the base of the barrel, free of threads to be later used. 190". The bolt recess is not yet machined to depth. Lathe Work I used my trusty old Clausing lathe and set the barrel up in my own design of roller bearing steady rest jaws directly surrounding the chamber. I located true barrel center with alive tail stock centered in the chamber. This showed no barrel runout.

A calibrated carriage stop, set to cut precisely 0.190" from the barrel shoulder and the end of the barrel shank, did the trick. This involved deepening of the bolt recess into the barrel, 190" and the bolt recess cut to proper depth for the Remington Model 700 bolt, all ready for reaming. thereby extending the new depth to the standard 0.150" common to a Model 700 Remington barrel. New Chamber Reaming Here I would be enlarging the existing chamber diameter 0.056" at the shoulder and 0.038" at the base.

Under the circumstances, the reamer live pilot would not come into play until well down the chamber. There was no chatter as the 30-degree shoulder of the Dave Manson Precision reamer (MansonReamers.com, was advanced into the 0.378" .222 Remington chamber base. Initial cuts revealed a perfectly centered, concentric chamber being formed. I used plenty of cutting fluid and cleaned the chips away often. The live pilot entered the leade smoothly until I removed the barrel from the lathe and finished reaming by hand.

Correct headspace was arrived at with the barrel shoulder/receiver at normal torque. Inspection of the chamber with a Hawkeye borescope (GradientLens.com, showed a perfect concentric, clean cut chamber with firing pin primer indentation at true center—something we don’t always see in a firearm, including factory cut chambers. The chamber neck was even and smooth. I place a lot of trust in Dave Manson’s reamers and this particular one had a special job to do.

Valkyrie Case Extraction The Valkyrie chambering would become the fifth barrel on a Model 700 Remington switch barrel rifle, with all cartridges they were chambered for sharing a .308 bolt face size. Not all such extractors in this bolt face

It can be an awful feeling to carelessly ream a chamber too deeply. Far configuration (SAAMI 0.473) are going to reliably extract a case head with the smaller size of the new .224 Valkyrie at 0.422". This bolt face was no exception. The Federal Valkyrie cases I worked with measured an actual 0.415". I had installed a Sakostyle extractor milled just a few thousandths deeper so the claw would engage both the new .224 Valkyrie case rims and also the larger diameter .308-size cases on this switch barrel setup.

All went well here and both size cases extracted 190", completely removing the bevel and restoring full thread depth. Below center: Measurement of a .308-size case rim at 0.473" compared with the 0.415". 224 Valkyrie showed the need for an extractor that would go deeper into the case rim. 224 Valkyrie. Larger case rims continue to extract well too. perfectly. Just how other .224 Valkyrie owners may cope with case extraction will likely require some careful thought.

Valkyrie Performance This was my first evaluation of Federal’s .224 Valkyrie cartridge, albeit in a 1:14 twist bore at this stage. I stayed with lighter bullets and compatible powders for this size case. The limited handloading information available to me was taken from the Sierra reloading tables posted on the Internet. This information was quite complete and comparable to the information published in the pages of the Sierra Rifle & Handgun Reloading Manual.

Some bullets grouped 0.300 MOA, including the Berger 52 grain, Sierra 52 grain and Shilen 52 grain. Of at least a half dozen suitable powders for this cartridge, I found Norma 201 appeared to perform very well. A charge of 27 grains generated 3,300 fps in the 23-inch barrel. The only 90 grain bullet I tried was one of the preloaded Match Kings sent to me by Federal Cartridge and it keyholed at (Continued on page 23)

a perfect 90 degree angle. This was expected with a slow 1:14 twist. Of course, these are but a few of the Clockwise from top, 6PPC- USA, .270 Winchester, .224 Valkyrie, 5mm/35 SMc, and .30-06 Springfield Improved at center. The action is a Model 700 Remington with single shot revision. This barrel was rechambered to .224 Valkyrie from .222 Remington. The rifle is capable of excellent accuracy with all barrels, including the newly chambered .224 Valkyrie.

Conclusions Here we see the practicality in the idea of converting a .222 Remington chamber to .224 Valkyrie while utilizing the existing barrel threads. A number of cartridge combinations can be used. For this action I’m using 6PPC-USA, .270 Winchester, .224 Valkyrie, 5mm/35 SMc, and .30-06 Springfield Improved. Making this chambering revision on select barrels of known accuracy can offer several interesting advantages at a modest cost to the shooter.

AG early loads produced for this new cartridge, with more to follow in other barrels and rifles, along with the PPC. It should prove to be most interesting.