Barrel Interchange-ablity

[eachief@sbcglobal.ne]

After about a year’s absence, thanks to the US Navy, I am back and starting back on some projects. I do have a question for you Enfield Experts: Can a No.1 MkIII barrel be mounted on a No. 4 and vice versa? I was organizing my parts and happened to have a variety of barrels in my hands at the same time. I looked and the No. 1 and No.4 barrels seem to be the same in the thread size and extractor cut. The No.4 is heavier at the Knox form of course. Anyway, just wondering.

Information

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[bigduke6]

BigDawgFSJ,

Before the answer to the question did you get anywhere nice in the last year? only ask as I,ve been round the world a few times myself.
They are different off the top of my head think they are about 180 degrees out on the thread start to the other so the knoxform would be underneath, and a bit more meat on the No4 than the SMLE as you stated. It can be done with some machine work etc, but for the hassle and where you are in the world I would check out Gunparts corp for the right one.

[eachief@sbcglobal.ne]

BigDuke6,
As a Seabee, we go where the Marines go. Both of my deployments have been to unpleasant places with unfriendly natives. The last one was to Kandahar. One good thing was we were there during the cooler part of the year.
The genesis of my question was that Sarco has 45-70 barrels for No.1 actions(which I have a few I could use), but I can only find a 45-70 magazine that fits a No.4 action. I don't know if the magazine would feed in the No.1 action.

[Bruce_in_Oz]

WARNING! DANGER!! Will Robinson.

Folks have been cheerfully winding an assortment of Enfield threaded barrels into just about anything with a 14 TPI hole for years. This does not make it "correct".

I do not have drawings for Martini Henrys or M Enfields. I DO have some drawings and tech data for SMLEs and No4s. The CRITICAL bit of data I do not have is for the indexing (qualifying) of the SMLE breech thread.

However: There IS a difference in the form of the thread between the No4 and the SMLE.

Viz.

SMLE:

Major diameter - .9995"
Root (minor) dia - .9024"
Effective (pitch) Dia. - .9574"
Pitch - .0714"
Crest Radius - .01411"
Root radius - .00804"
T.P.I. - 14
Included flank angle - 49deg 40min.
Thread start - REFER TO GAUGE (Anyone have that drawing???)

The above data comes from a drawing that in turn refers to Specification S.A. 1003B., which, of course, I do not have.


The No. 4 barrel reads as follows:

Major Dia. - 1.000" / .9937"
Form - WHITWORTH!!!!! (55 DEG included flank angle)
Effective (pitch) dia. - .9543" / .507"
Minor Dia. - .9086 / .9015"
Concentricity tolerance - .003" MMC
The thread datum is derived from a point on the breeching shoulder, 10deg 18min above the horizontal axis.

The nominal major diameter and pitch are about the only common features of these two threads.

[eachief@sbcglobal.ne]

Bruce,
Tanks for the VERY informative and authoritative research. Oh Well, A single shot is not all that bad.

[smellie]

If you are really going to do such a thing (and I shudder, being of the opinion that even the sorriest wreck should be restored to 'new'), you should know that there is a very good chance that you don't have to settle for a single-shot.

In this part of the world, old Lee-Enfields still are around in numbers, especially if you know a shop-owner who TAKES them in trade and then buries them in the back room because he makes more on a $1200 rifle than he does on a $75 rifle. Besides, he knows that he can sell them to me and I wouldn't buy a $1200 even if I could afford it: too much Scots in the ancestry! And people generally can't tell one magazine from another. The last Number 4 I bought had a fully-functional SMLE magazine in it. They are that close, really. If a fellow were doing the conversion you contemplate (and I shudder once again!) I would think that any mods in order to use 'the other magazine' would be very minor. Get it in and it will feed just fine.

Have fun!

Now, where did I put that SR-D jug? Grumble, grumble... Forty-five-seventy, of all things! Oh well, James Paris Lee did it, so I guess it's okay. Forty-three Spanish would be even better....

Hmmmmmm.....