Most of my BCs have a web thickness at the breech of 1/16" or slightly less and a web thickness at the muzzle of 5/32". The 1/16 dia music wire pin requires a different bbl lug and a #6-32 front lock bolt requires a shallow groove in the bbl to accommodate the 1/16 or slightly less web thickness at the breech. By the way..... many Lehighs have a 1/16" or less thick web at the breech. Thin webs require very accurate layouts and drilling because there isn't any leeway.
Both web thicknesses result in both the lower and upper forestock's bottom lines having a taper towards the muzzle.....a slenderizing effect.
In fact, seeing how slender the BCs are, my last Lancaster had the same webs and has the same tapers toward the muzzle......Fred
I guess I'm just enamored w/ slender LRs.....having not built any early LRs.
fred