Loading the .223 Remington to .22 WMR Velocities
Date: Nov 03 2010
Handloading the .223 Remington with inexpensive cast lead alloy bullets to duplicate the trajectory of the .22 magnum saves money over the price of .22 WMR cartridges. Years ago I used to think I was daft to cast these little .22-caliber bullets the size of small vitamin pills when jacketed bullets cost about 5¢ apiece. But the outlay for these jacketed bullets has doubled and even tripled during the last couple of years. The price tag of .22 WMR (and .17 Hornady Magnum Rimfire) cartridges has also gone through the roof with costs of 19 to 36¢ per shot.
So my .22-caliber moulds are back at work again casting bullets. A breakdown of the cost of a .223 cartridge loaded with a cast bullet is approximately 2 to 4¢ for propellant, 3¢ for a primer, 2¢ for a gas check and 1¢ for lead alloy, or about 10¢ per shot. That’s half to a third the cost of .22 WMR cartridges. The fun and fulfillment of handloading the cartridges is an added bonus.
The .22 WMR shooting 34-grain bullets at 2,120 fps has a trajectory of about an inch high at 50 yards, right on aim at 100 yards, 5 inches low at 150 yards and 17 inches low at 200 yards. Forty-grain bullets from the .22 WMR with a muzzle velocity of 1,910 fps drop a few more inches at 150 and 200 yards. These trajectories can be matched with a 55-grain cast bullet with a muzzle velocity of about 2,000 fps. Cranking the velocity of the 55-grain cast bullet up to 2,200 fps nearly matches the flatter trajectory of the .17 HMR.
Relatively fast burning pistol-type powders usually produce good accuracy with cast bullets at up to 2,000 fps in .223. Unique is a favorite. Seven grains of this bulky powder fill three-quarters of a .223 case, generate speeds of nearly 2,000 fps and shoot great. With the RCBS- 55-SP bullet and 7.0 grains of Unique, groups are as tight as .59 inch at 100 yards. I don’t think I’ve ever shot a group much larger than an inch after years of shooting this load in several .223 rifles. However, pressures rapidly increase to over 35,000 CUP with Unique when velocities are stepped up over 2,000. Eight grains of Unique bumped the RCBS bullet to 2,093 fps, and group size enlarged to 1.48 inches.
I started using Accurate 5744 only a year or so ago, but it’s rapidly becoming a preferred cast bullet propellant. It is a slower-burning powder than Unique. Pressures are about 20,000 psi with 12.0 grains of 5744 and the Lyman 225646 55-grain cast bullet in the .223. That load shot a 1.05-inch group at 100 yards, with four of the bullets in .61 inch.
Other good powders with cast bullets include Varget, TAC and X-Terminator. These powders, however, do require charge weights about twice as heavy as Unique to reach 2,000 fps with a .22-caliber cast bullet. That’s a significant increase in cost if you’re pinching pennies.
The .223 doesn’t burn much of any of these powders with cast bullets. Some amounts are similar to those loaded in the .357 S&W Magnum. So I tried a small pistol primer with several powders to find if the primers provided enough gas to ignite these powders and at the same time reduce pressure and turbulence to produce more even speeds. That was the case, at least somewhat, with Unique. Winchester Small Pistol primers have an extreme velocity spread of 55 fps compared to 68 fps for Winchester Small Rifle primers. As Table I shows, small rifle primers produced a narrower velocity spread with other powders and lead alloy 55-grain bullets in the .223.