Fitting a barrel to a #1 mk3

[bigduke6]

Removing a barrel from a No1 always seemed a breeze compared with a No4.....

[Bruce_in_Oz]

I always understood that SMLEs breech internally (at the rear of the threaded tenon of the barrel) as does the Mauser 98 (when it left the factory with its original, Whitworth-threaded barrel), whereas the No4 breeches on the front of the receiver / body ring.

This is, apparently, why you will sometimes see a tiny amount of "daylight" between a SMLE body and the barrel Knox form.

Never had many problems removing barrels from No1 / SMLE types unless there was a ludicrous amount of rust present, with all that may signify. Biggest drama has been finding decent replacement items.

Next "issue" is scrabbling through the bolt-head collection to find one that will provide both acceptable headspace AND alignment to the bolt body.

This is on top of assuming that the body itself has not been flogged so hard that the "load-bearing" surfaces on the locking shoulders are worn beyond spec.

Removing No4 (and P-14) barrels can provide many opportunities for exercising certain "colourful" parts of the vocabulary.

A serious set of tooling is essential.

[tbonesmith]

"Removing No4 (and P-14) barrels can provide many opportunities for exercising certain "colourful" parts of the vocabulary.

A serious set of tooling is essential.[/QUOTE]

I pulled an Eddystone P14 barrel the other night and Holy Moses was it tight. In the end i took the releif cut then it was no drama, and still plenty of oil on the threads and interface... just TIGHT mate...

[brent65]

"Removing No4 (and P-14) barrels can provide many opportunities for exercising certain "colourful" parts of the vocabulary.

A serious set of tooling is essential.

I pulled an Eddystone P14 barrel the other night and Holy Moses was it tight. In the end i took the releif cut then it was no drama, and still plenty of oil on the threads and interface... just TIGHT mate...[/QUOTE]

It wasn't mine then?

[Son]

When the barrel and receiver are originally breached up, they are tightened until the barrel indexes. I've never pulled a No4 barrel, but then the instruction for that is to take the relief cut out of the bit you don't want and it's easy from there. As noted above, the SMLE barrel locks to the inside face and cannot be relieved to make it easy. I have come across some absolute mongrels to remove, but have never failed or damaged a receiver or barrel either. My point here is, when breaching up a new barrel, it will usually index and be tight. Occasionally, using a pull off barrel and used receiver, a barrel will turn past clocking before it is tight. I think in these cases probably both had been very tight before and left the threads stretched so the parts. I found a supply of shims years ago for dealing with this. They came in two sizes, .002" and .005". I have had a couple that needed the .005" that couldn't be head spaced afterwards with available bolt heads, so at that you may be looking at needing a different barrel or setting it back a thread ( or more accurately, .005" less than one thread pitch) then re chambering.
Problem is, my supply of shims ran out. I have not been able to find more, but might have a substitute, yet to be confirmed.

Anyway, just some ramblings to add weight to the discussions on how complex the job can be...

[Steve H. in N.Y.]

Son,
I've gotten shims of various thicknesses from an industrial supply house. 5/8" inside diameter is about right and the outer can be carefully trimmed with a pair of good scissors. I imagine something like this would be available in your part of the world also.

McMaster-Carr

[Son]

I have recently found some hardened muzzle brake shims are very close to the same OD, and a bare fraction larger in ID. It does give them a fractionally smaller surface contact area... And I haven't tried to fit one yet, but only after use and checking will I be able to be sure it isn't a concern. The sizes of the smaller ones are stated as .006" and .004" nominal, so that should be workable.
I suppose if a barrel was torqued up with one of them and then became loose over time/ use, that would be the only way to know.