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Legacy Member
No.4 Mk1 Barrel and receiver machinist drawings
Hello Gents, does anyone have the machinist drawings for the no.4 mk1 receiver and barrel tucked away somewhere?
I have a project I am working on and they would sure come in handy right now. Once my project is done and tested I will post pictures and a write up.
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02-11-2019 10:40 PM
# ADS
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Legacy Member
I am surprised that nobody has either drawing. Oh well, I guess I will have to measure a selection of each to figure out tolerances and make my own drawings.
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Sorry nobody has come up trumps for you Mike. I have quite a lot of stuff such as Instructions to Armourers, EMERS & so on but I don't know of anyone who has the engineering drawings for the two major rifle components themselves. I hope you manage to work them out.
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Legacy Member
That’s the way it goes sometimes. I was just surprised as this forum is astounding with the amount of knowledge that is here. It surprises me every time I login.
I’m looking at having a run of barrels made with the same external dimensions, bayonet lugs, front sight base etc for the no4 mk1 that are 5r .302” bore size, .3095” groove to run the 174SMK but needed a drawing first and was looking for the original. Measuring many samples will provide the tolerances just the same, just takes longer.
Once I get my drawing done and price it out I will report back.
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Thank You to Parker-Hale Mike For This Useful Post:
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Well good luck. If you can get to the stage of producing complete tight tolerance military profile barrels you'll have a ready market. This side of the pond for the cost of rebarrelling & re-proofing your No4 you can buy a complete new rifle, which is a bit of a disincentive unless your existing rifle holds sentimental value or is particularly desirable, like a No 4 T.
Please keep us posted. I, for one, am interested to know how it goes.
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Contributing Member
I had external profile drawings supplied to me one time from a popular manufacturer of vintage barrels and they provided them to me. All I had done was contact them about some fitting questions for external bands and collars and the similarity between two different product offerings. It was very helpful and I was impressed they were able to oblige the same day. Helped them sell some more barrels too.
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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!
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Advisory Panel
Why not just buy new No.4 barrels from Criterion? They are perfect. The sample barrel I tested shot consistent groups of 1.75"-2" using the 174 SMK at 100 yards with a Mk.1 sight, AJP 8/53 backsight attachment and camera diopeter eyepiece. I have a sneaking suspicion as I've been down the same road before with these type projects that you won't be able to get them done within a reasonable price range unless you commit to producing a large quantity and the demand really isn't there as it's already been filled by CBI and Lothar Walther. I DO wish you luck with the project.
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Advisory Panel
Why not just buy new No.4 barrels from Criterion?
Exactly.
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Legacy Member
Why not just buy new No.4 barrels from Criterion? They are perfect. The sample barrel I tested shot consistent groups of 1.75"-2" using the 174 SMK at 100 yards with a Mk.1 sight, AJP 8/53 backsight attachment and camera diopeter eyepiece. I have a sneaking suspicion as I've been down the same road before with these type projects that you won't be able to get them done within a reasonable price range unless you commit to producing a large quantity and the demand really isn't there as it's already been filled by CBI and Lothar Walther. I DO wish you luck with the project.
Have you slugged a new Criterion? If so what dimensions did you measure out for grooves? Was it larger than the dimensions I quoted by at least a couple thou? The one I measured plus other people I have talked with confirmed my measurements.
There is a reason I am trying to make the barrels I am. I don’t want a milspec barrel.
I am trying to see how accurate I can make a .303 while still retaining the stock appearance.
Who knows. Maybe I will get no where with this project, maybe I will. All I can do is try.
Last edited by Parker-Hale Mike; 02-18-2019 at 09:21 PM.
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