Considering some version of lapping a Lee Enfield barrel?

[Bruce_in_Oz]

Lapping a Lee Enfield barrel?

By my reading, SMLE barrels were "lapped" from Day Onoe.

Rhe "reason" was that the boffins were trying to claw back the muzzzle velocity lost when th e barrel was abbreviated from its priot "long' dimension.

This lapping was supposed to be "progressive", with the BORE diameter increasing towards the muzzle. B4ear in mind, this was the same era in which the Patt '03 bayonet was deemed to "shortfor actual combat. and the '07 clone of the Arisaka Type 30 bayonet introduced to regain the spirit of the pike. I have had Lithgow "H" barrels here , new in their packaging, that were measurably "belled" at the muzzle.

Arguments rage about bore-lapping? My reading indicates that those barrel makers that lap their barrels, do so on "over-lenght blanks, then lop off the first and last inch or so, to remove such belling that is caused by "runout" in the process.

Several rifle-builders regard the entire practice as "pre-wearing" an otherwise good barrel.

If you ever get to see the full process of "Hammer-forging' of barrels check out the "lapping machines".

These are ONLY used to precision polish the internal bore of the stumpy "blank", BEFORE it gets pounded into barrel (and chamber) shape. Interestingly these "stubby' barrel lapping machines operate vertically; with the "lap" slurping up the abrasive "mud" on each stroke.