I have several L&R locks. they do function quite well. I have sent two back to be updated and have flash guards installed. I now have the forged mainsprings and updated tumblers. Good sparkers. I also have an L&R Manton lock in my SMR. Sometimes its the percussion lock modified from a flintlock or a flintlock. both work well. Of course some polishing was in order and in the Late English locks I have to be sure to position the flint in the lock at an optimal distance from the frizzen for best performance.