These TPS are pretty elusive, though Erfurt is probably the most prolific, - interestingly DWM is also.
Many think this was a latewar expedient, but so far as trends suggest it was more common in 1916 than 1918, but the disparity is not great. Erfurt and Amberg show up in 1918 the most, WMO a very late 17 (ff-block), but this less frequent use in 1918 may be because so many mfg's dropped G98 production by 1918. Erfurt 1918's are all 98a obviously, so in real terms this leaves Amberg the main 1918 user. (DWM and Danzig also curtailed G98 production in 1918, so this could play more of an influence is the relative rarity in 1918 as if G98 production hadn't diminished one wonders if it would have been more common -then too, Amberg's may also be more prominent because so few 1918 G98;s have survived w/ original stocks, only Amberg is commonly seen in upper grades from 1918)
Really a neat subject, one where speculation plays a greater role than usual!
