1803 Harpers Ferry Sau Paulo repro. When I first got it, sear would land in half cock notch on the tumbler almost every time. I removed the sear and squared and polished the knife edge. Now I can get about 200 successful shots before it starts getting stuck in the half cock position. Last night, I squared the knife edge and polished it with a leather strop. All seems fine again. Is there something I can do to fix this? Maybe heat treat the sear or polish the tumbler. Anyone have any thoughts? The number 110 is stamped on two places inside the lock. Maybe I can find a replacement part that works better. Many thanks.