Bucks Co. rifles are found w/ both Germanic and English trade locks. The large Siler lock is at the upper end of the "big" scale, but is often used and would certainly be correct. The English trade "Tulip lock" (called that due to the stylized tulip engraving) is often encountered. Remember, Bucks Co. is just north of Philadelphia, so a wide variety of locks, barrels etc. were available in that area. A perfect Germanic lock would be something between a small Siler and a large Siler, of course that is my opinion. I often use the late (classic) Ketland from chambers, as it is one darn good lock. Ron