In European rifles of the early to mid 18th century I've seen, most sidplates are either complex forms with piercings (serpentine) or the rear portion behind the rear lock bolt is essentially triangular in shape. The early Christians Spring sideplates are very similar to European forms. In contrast the classic Lancaster sideplate is rectangular in its termination at the tail, as are many Berks county sideplates.
To me that raises the question, whether the square tailed sideplate is an American design or carried from Europe, and how early it is found on American rifles. The Reading-attributed RCA 21, and the earliest Dickerts are the earliest rifles I can think of with a squared off sideplate tail. Anyone have anything on Euro rifles with this style sideplate? Seems likely it was in place in Lancaster and Reading by the 1760's.
