Inverted rifling?

[119er]

I have a No 4 Mk1* 86C serial Savage made in '43 I believe with a two groove barrel. I have yet to fire this weapon. Upon initial cleaning and inspection I noticed that the brush nor the Jag/patch would twist with the rifling. When I finished and looked at the bore it seemed backwards and it is. The lands and grooves are opposite of what is normal. The grooves are narrow and the lands are are wide. See illustration please. I used a pick in the muzzle to verify I was not seeing things. Any ideas?Attachment 23174Attachment 23173

Information

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[jmoore]

That's normal for two groove rifling. No worries!

[RJW NZ]

lol, there's nothing normal looking about 2 groove rifling, is there?

[TonyE]

Maybe the clue is two groove rifling!

Regards
TonyE

[buffdog]

Go fire it. Tests were made to determine the accuracy of the Two Groove barrels, and it was found that these rifles were equal in accuracy to the regular Enfield barrel.

Also, if you shoot cast bullets, some shooters have found that the two groove barrel is more accurate with the lead slugs.

Each rifle is different. You have to shoot them to see what they will do.

Don't worry about the grooves. All is O.K. in Lee-Enfield land.
.

[119er]

I am new to the Enfield and wanted to make sure this was normal! Doesnt it seem to be an excessively wide bearing surface? Is this equal to what would be in a 4 or 5 groove barrel in terms of surface area? I don't want to beat a dead horse, but I can't leave it alone! Thanks for the help!

[jmoore]

Two groove 1903a3 barrels aren't much different, but have shallower grooves!

[Parashooter]

See Hatcher's Notebook pages 17 and 24 in PDF (8 and 15 in book).

Essentially, the grooves in a normal 2-groove Savage barrel occupy about 1/3 the circumference of the bore (unlike your drawing showing tiny grooves) and are supposed to be ~.313" in diameter. With the bore nominally .303" in diameter, the average diameter is ((.303x2)+.313)/3=.3063".

In the normal Enfield-pattern 5-groove barrel of the same bore/groove dimensions, the lands and grooves are equal width, so the average is (.303+.313)/2=.308".

Wartime barrels, however, are frequently oversize, running .315" or more in groove diameter. Slug your bore to find out its dimensions, including the proportion of lands and grooves as part of the bore's circumference, figure the average, and you will be way ahead of most L-E novices.