The .224 Montgomery is a wildcat cartridge created by IHMSA competitor and instructor Tim Montgomery. The case is based on the .25 ACP, necked down to accept .224 caliber bullets, which are typically found in rifle cartridges like the .223 Remington / 5.56x45mm NATO and the .22 Hornet.
A quote by Tim Montgomery can be found in Frank Barnes' book "Cartridges of the World". He says, “I have been shooting this cartridge since 1990, and it is not too hard to get a few sub-MOA groups out of each range session.”
Tim Montgomery himself, over at CartridgeCollectors.org forum discussed a number of loads he's experimented with. For example, "30 grain bullets from Berger Bullets can be pushed over 2,000 feet per second... but my most accurate loads use 40 grain bullets to about 1600 to 1700 fps."
He fires these rounds from a custom-reamed Thompson/Center Contender with 12-inch barrel and 1:12 twist.
|Bullet (Grains)||Velocity (FPS)||Energy (Foot Pounds)|
|30 Gr||2,000 fps||266.5 ft lbs|
|40 Gr||1,700 fps||256.75 ft lbs|