No.4 Mk1 Barrel and receiver machinist drawings

[Bruce_in_Oz]

I suspect it is a seller's market.

These drawings have been around for decades, kept and copied by "enthusiasts" who just wanted to preserve the information, or have an interesting bit of artwork to hang on their shed wall.

Tempus fugit and all that jazz; now, they are worth money to entrepreneurial types who have rightly observed the growing market.

I have copies, shabby but readable, of the full drawings for both the US/Canadian Mk2 body and the late Fazackerley Mk 3 body. HOWEVER what is "unobtanium" is the supplementary information for each drawing; all the little "notes" that detail the finer points of manufacture. Datum points for qualified threads are a good one. Some even show the shape and path of specialized cutting tools. Drawings for earlier goodies like SMLEs are MUCH worse, with the REAL good stuff lost in the "process books".

Barrel drawings? Oddly enough, harder to find. But, an afternoon with a couple of representative samples in a good metrology shop will get you a data "cloud" to feed a CAD system. Digital CMM probes have been "talking to" CAD programmes for a couple of decades now. The general exterior is pretty simple; getting the breech thread indexing to tolerances (there are TWO; one for "new" barrels, one for "replacement" barrels) is a whole other game.

The catch is that the bodies, in particular, are seriously complex shapes. Amortizing the set-up and tooling costs will require the sale of a LOT of product. Barrels, less so, but piggy-banks will get a flogging. Any competent machinist / gunsmith could make a generic No 4 barrel, complete with correctly-cut bayonet lugs, from a blank, in a day. At a hundred bucks an hour..... A GOOD CNC shop could churn them out like sausages, and probably to finer tolerances, but, unless you can cough up for a "minimum run", that will have the "set-up" / programming costs built in, they won't even think about it.

Then there is the cost of a batch of "correctly" rifled blanks. A thousand dollars will get you a button of your desired form, twist-rate and "direction", and then the fun starts. Been there, done that....OUCH!

Good luck!