Many moons ago at Browning Barracks there was a indoor range with a cine simulator. The rifles used were standard L1A1s with .22 rim-fire converters fitted, made by Heckler and Koch; These appeared to be easily removable as they were simply comprised of a smaller inner barrel and breech. I assume the magazine was an original 7.62 mm mag converted also. Are these still available and can they be permanently fitted to, say, a FN FAL or similar? Iâve only ever held a FAC for .22 rim-fire and Iâm (possibly naively ) wondering how easy it would be to convert larger military rifles to my permitted calibre. A quick google revealed not much other than a bloke who fires .22 air rifles pellets with a .223 cartridge!