L&R Queen Anne lock. Left hand. Its a darn better lock than the right hand version , go figure....disassemble it . Measure thickness of bolster , widest part of lock and scribe on wood the length of lock , slab this wood off with saw ...now mark length of lock and remark your lines for barrel bottom and web ...Mark the breech face on barrel , and proposed touch hole , then drill through wood so you can see it and aim for it . barrel back in...mark where mainspring ends , front of spring , on front lock plate , any where forward of this is good for front lock bolt . Try to make lock plate eve. , looking g good and front where front bolt through web can hit sweet spot on front of plate ...the pencil mark flash fence , top of bolster front and rear of bolster ....take off plate measure bolster height , mark , then scribe line for bottom of bolster .... Inlet this down to the barrel . When you get close to barrel use old chisel , sacrifice chisel , so you dont hurt your good chisel