Recently bought 2 muskets at a yard sale(great price!) One was a `701s vintage Miroku Brown Bess. Other I`d appreciate info on may be similar era. It`s an 1864 Spr w/case hard lock & hammer . Fit/finish is good-only part don`t like is 2 piece stock( found after got home & took barrel out of stock(have you heardof them coming apart?) Only markings on bbl. are "Navy Arms Ridgefield NJ USA" & serial #0450.Absolutely no other marks including no proofs! Fired @ 25 yd range w/ 50 gr 3f & 575213, dead center windage & 2'' high, excelent group. Do I have a Jap. made rifle? What`s the concensus on quality?