***Correction.
After just examining my later JPS collection. My “t” block bcd 4 marked receiver actually has a astrawerke bolt body (stamped “1” on the bottom of the root) and has the typical, but faint JPS firing proof on the back.
My “u” block ce44 also has a astrawerke (1) supplied bolt and much more subcontractor (like “i” for Elite D.) marked parts than my earlier examples.
My ce44 “r” block is the oddity in which it has a sloppy solder on the rear sight sleeve, an unmarked bolt body and no firing proof on the back of the bolt root. It has what appears to be a capital “M” on back of the bolt root. I know Mauser Oberndorf bolt bodies have the “MI” on the rear lug, but this one has me stumped as it’s on the back of the bolt root, just the “M” and no FP.
Ar43 receiver finished by Sauer in 44 “c” block. The bolt exhibits poor finishing. Some kind of mark on the bottom of the root and typical JPS firing proof on the back.
I’ve included some pics of the markings/features on these bolts….
First 5 are the “r” block. Next 3 are the bcd4. Last 3 are the ar43…