i don't remember seeing a thread specific to "tuning" a GPR lock, but i've had Many of 'em over the decades. as you may know, the lyman GPR is an investarms product (same as DGW and cabelas) and imho it's about the best of the offshore production trad ml's.
if you've taken the lock completely apart, cleaned it out, polished only the working movements, stuck it all back together with some form of light lubricant, that's about it. i would also check the lock mortise, to make sure the cock isn't in any way touching the stock during it's travel to the hammer steel.
these box-stock GPR flint locks are typically fast and reliable right outta the box. you'll find some threads in this forum on a pair of hawken GPR and DGW kits i assembled, along with videos - see how fast she fires, and that's with 3f in the tube AND pan!
