Oberndorf "broken firing proof"
The Oberndorf "broken firing proof" occurs late in 1944 'l' block production and into early 1945 (byf 45 coded) production.
I am at work now and do not have access to my image library but the swastika is missing - likely as a result of a damaged firing proof stamp die.
This "broken firing proof" helped confirm that there were overlaps in production at Mauser with multiple codes in process at one time, in this
case both byf44 'l' block and byf45 early no-letter series.
This also reinforced our opinion that production at Mauser was non-linear with certain segments of the serial number ranges being produced not in numerical
order but rather in batch order.
I borrowed an image from an old thread showing a very late 'l' block with a low 4-digit number.
Notice the "broken FP".