"Einstecklauf 24 mit Zeimunition Kaliber 5,6mm". Can anyone steer me in the direction of a good reference book with information on the Ermawerke .22 caliber conversion unit for the KAR 98k? Also, anyone have knowledge of Heeres WaffenAmpt acceptance markings, or a book that covers the subject thoroughly? I picked up one of these units (after searching for a good one for 15+ years). ERMA, Erfurt 1937 marked - it's matching throughout and minty, right as rain in every way. However, here's the rub. It's 'ampted in a bizzilion places with WaA77, except for one small part on the mag housing assembly which is WaA 280. Like I said, it's correct beyond a doubt - never been messed with. The only reference I have that has anything close on this is GERMAN SMALL ARMS by AJR Cormack. "Production continued for some time as one unit is marked Erma Erfurt 1937 WaA 280" Just wondering if anyone could provide some insight as to the 'ampts used at ERMA, when they used which one, when they changed, etc.