Hi Yung_Flint
The reason I suggested going to a stock without the lock mortice inletted is that the touchhole needs to be centered at the so called sunset position .
On a pre-carve I like to get the barrel settled in ,sometimes deeper than it comes pre- inlet as frequently the web between the ramrod hole and the bottom of the barrel is too generous .This is done deliberately by the stock shaper as it is better to have too thick of a web than to have the ramrod hole poke through into the barrel channel . Less wood stock is wasted that way . Wood wasted is money lost. It's also worth checking to see where the ramrod hole actually ended up .Sometimes you have to fix that first or reject the stock before you even start cutting.
By the time you get the barrel to where it should be the lock mortice lock is often not in the correct position anymore .
The touchhole position in the barrel should be ...
1)centered on the barrel flat
2) just in front of the breech plug face
A properly positioned lock should....
1) have the front screw pass through the web of wood between the barrel and the ramrod hole
2) the rear screw should pass behind or if needed with a relief hole drilled through the breech plug turning lug , or a notch through the same behind the barrel . These two screws snug the flintlock itself to the barrel flat so there is no gap . You don't want any possibility of live powder getting trickled down into the lock mortice and then igniting blowing the lock off .
3) the imaginary line across the top of the pan should bisect the either bottom (hunters seem to prefer this )or the center (for target shooters ) of the touchhole .
The build books do a better job of explaining this with pictures , some of the terminology may not even make sense yet .
Add to that is some breech plugs come overly long messing up the geometry .(means how the parts are placed and how it effects the final shape of the gun ) The lock gets placed too far forward .Sure it might work but it looks a bit off.
Or the breech plug as received may not be properly installed ,meaning the face of the plug is not fully flush with the back of the barrel. Most good barrel makers do this correctly .If you order the plug installed but it's up to you to verify this before investing your time .If the threads are exposed hot gas erosion and rust will result and your patches will hang up in the barrel .
That's bad.
Guns that work well are built step upon step .Correct placement means your gun works in the end . Fully inletted stocks would seem to take the guess work out but too many steps are done at once . The placement of the lock is super critical to function .Further the stock shaper may have no clue as to what components you are actually using ,it's all kind of a guess anyway.
The only rifle stocks fully insetted (well 90% anyway ) that I had any luck with was Dunlap woodcrafts Springfield stocks for rifle muskets using original spec parts . But that's slightly off topic and Dunlap did have a good idea of what parts one would be actually using .The wonders of early parts interchangeability and armory genius .
You are recreating something from earlier '' world made by hand '' its a different thing and pre-industrial craft .
Trade guns are easier to build than a long rifle and are more forgiving . I would screw mount the butt plate ,many originals were done this way . Screw mounting is easier than nailing the buttplate on .
Luckily screws are cheap and machine made now not and not hand filed .Maybe I had shoed horses part time I might feel differently.
Anyway I seem to learn the hard way so save yourself the grief and learn from my mistakes .
I will note I have built a number of guns from inexpensive precarved stocks when I started and from- the -blank builds but have no direct with Mr Clay Smiths kits . But I started on a budget a long time ago before some of the better stock shaping machinery was available.Even so I personally insist on inletting the lock myself .
Best regards Stuart