Bolt guns in 223 Remington have carried training and match duty for years because the cartridge is soft shooting and easy to run in volume, and MDT's Gen2 polymer AICS magazine keeps them running. 12rds load into an AICS pattern body that fits MDT chassis and other bottom metal cut to the Accuracy International footprint.The Gen2 polymer line makes keeping a spare simple, and the lighter body is a bonus on a trainer that gets carried through positional drills. Feed geometry is tuned for the short, fat stack that 223 makes in a short action magazine, which is exactly where generic magazines tend to stumble.