Most first name makers brought in box locks from Birmingham trade, and many second lever makers did as well. The most obvious is when they are engraved "shot and regulated" by H&H, but I doubt any of the top five or six makers would bother to make a box lock when they were so easy to bring in either in the white of completely finished. That allowed them to concentrate on side plate guns. Who needs to be master of all things? And even then box locks were not sold as their best quality but rather third or fourth level to meet the request of their clients for a gun for a nephew or game keeper. They still wanted the name to impress but did not want to spend a lot.
But we assume side plate gun and box locks could not both be made to the highest standards. They could and some box locks clearly were but the box lock was so much easier and cheaper to make and stock, it flooded the market on the low price end. We had the Crescent side plate but I have not seen the British equivalent. High grade box locks tend to be rare, like one out of 50, or 100 box locks were top grade, finished to the highest level.
