SMLE barrel question

[RalphEd]

I have this No4 Mk1 I just picked up. It's a 1944 BSA with a 2-groove barrel. I have some questions about it and a 98 Krag I have (I'll post those on the Krag side, if I can find it).

I slugged it with a lead round ball and it is measuring .3076 bore and .3205 groove-to-groove. Is this typical?

Bolt face has a no 3 on it. Is this headspace condition? What's it mean or signify?

Do SMLE's commonly stretch cases? (I had heard case life isn't good with them)

Where can I get cases?

Thanks all,
Ralph Ed

Information

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[Bruce_in_Oz]

RalphEd:

.3076" / .3205" bore and groove; those are seriously generous dimensions!

My info is that a "standard" 5-groove No4 barrel should have dimensions of: Bore diameter - 0.301" Min, 0.304" Max; Groove diameter - 0.313 Min, 0.319" Max.

I suspect that 2-groove barrels have different basic tolerances and, supposedly being an "economy" measure, may have been allowed a bit extra. I also know that genuine military Mk7 projectiles expand a bit on firing and will fill a reasonable amount of space.

Whatever you do, avoid shooting soft-point / hollow-point boat-tailed projectiles in that barrel. The gas-bleed around the closed boat tail will cause gas-cutting at the chamber throat and subsequent loss of accuracy. Stick with flat based bullets.

The No3 bolthead would indicate that the assembly of barrel, receiver and bolt-body is at the maximum end of normal Mil-Spec limits regarding headspace. As far as I know, there is nothing (legitimate) above a No3 bolthead. However, there are tolerances within each number range and you can find "long' and "short" examples of each nominal size (if you are lucky).

Pretty much ALL rifles will show SOME stretch of cases that have any "bottleneck" in their shape. The Lee Enfield action has a bit more "give" due to its rear lockup. However, as the .303 is a rimmed case, you can have also minimal "headspace" but suffer excessive case expansion due to a chamber made to maximum tolerances. In a military, non-reloading situation, unless carried to extremes, this does not matter much with regard to safety. If you want to recycle your brass as much as possible, there will be "issues". Be aware that some sources of the dwindling supply of surplus rifles may not be above polishing out a pitted chamber to get a better-looking final product. Again, in frenzied war-time production, chamber reamers would have been made to "Max" size initially. They would then be periodically re-sharpened until they failed the minimum gauging, at which point they would be scrapped or re-cut into another smaller tool for a different job.

As for cases, most major ammo makers supply them. See the various posting on this site for the pros and cons of various brands. Your local gun shop should be able to get them in or, as empty brass contains no explosive, you should be able to mail-order them from some of the big boys.

Anyway, welcome to the wonderfully exciting and sometimes eccentric world of the Lee Enfield.

[Alan de Enfield]

The 'official' figures for a 5-groover