US 1917 Barrel Specs?

[Char-Gar]

Yesterday a fellow shooter was waxing wise about the 1917 and said, they had left over P14 .303 barrels that were chambered for 30-06 and hence oversized. I didn't think this was true, or at least not generally so, but I didn't call his hand and I was not 100% certain.

What is the straight skinny on this issue?

[Pepe Ray]

Elmer Kieth reported finding this to be true back when he was writing for G&A.
Pepe Ray

[StarMetal]

According to no less an authority than Hatcher's Notebook:

We retained the Enfield form of rifling, but changed the bore and groove dimensions to suit our own bullet diameter of .3086 inch. To accomplish this we changed the bore from .303 inch to .300, and made the grooves .005 inch deep instead of .0058 as in the .303

Hatcher goes on to make the point that with the five-groove rifing there's no placce where groove diameter can be measured directly, but that in an overall sense the Enfield barrels were actually
...somewhat tighter than the rifling we had been using on the M 1903...because after careful tests it seemed to give the best results for that form of rifling with the diameter of bullet we were already using.

Hatcher goes on to say:

This has been gone into at some length because we so often see in print the erroneous statement that the 1917 has a bore that is too loose because we "used the British dimensions" ...

All of the original 1917s were five groove. On refurbishment some were changed to four groove with barrels made by Hi-Standard Manufacturing, and some were changed to 2 groove with the Johnson Automatics barrels.

The Remington Model 30 was a post WWI sporter based on the M17 action - Remington had vast inventory and production capacity for these when WWI ended, so stuck a rather skinny sporter stock on a lightly modified M17 and put them on the market in 1921. They were refined a bit further as time went on, as the Model 30 Express and later 30S and other variants, and the line was finally discontinued about 1941.

[Multigunner]

Townsend Whelen found that many M1917 bores miked at .310, which was common for the Krag .30 rifles as well.
While the M1917 barrels were intended to be compatable with .308 nominal bullets the bores were slightly larger than the standard for the 1903 Springfield.

Its not unlikely that more than a few bores were a tad oversized and could measure the same as the .303 P-14 barrels.
Its also not unlikely that a few leftover .303 barrel blanks might be finished out as M1917 barrels, but unlikely that finished P-14 barrels would be redone at the breech to match the M1917 breech.

The Enfield pattern rifling coupled with single base powders of .30-06 ammunition of the period resulted in an uncommonly long useful bore life, and at one time many ordnance officers were in favor of adopting the enfield rifling for all US .30 caliber rifles.

It was common to rechamber M1917 actions for .30 caliber magnum cartridges. I suspect that the deeper grooves and broader lands helped in resisting erosion of the hotter magnum loadings.

If a .303 rifle had been made using the M1917 bore dimensions it would probably have been a very accurate rifle, since the .310 major diameter would be much better suited to bullets of .311 or less, and undersized bullets were common.

[Char-Gar]

Joe... Thanks. I knew I had read somewhere about the rifling style being British, but bore and groove changed to American 30 caliber. I do have a copy of Hatcher's notebook and remember now where I read that. I just couldn't remember yesterday, and didn't feel like challenging the guy without being certain of my facts and source.

Book and page Counselor...book and page! Those old habits stick with me. I don't mind expressing my opnion on anything, as long as it is labled as opinion, but when it comes to facts, I don't speak unless I can back up what I say if challenged.

[challenger_i]

If a .303 rifle had been made using the M1917 bore dimensions it would probably have been a very accurate rifle, since the .310 major diameter would be much better suited to bullets of .311 or less, and undersized bullets were common.

I have to agree with this statement, as I have a commercial Martini, that slugs out at .309, and that puppy will drive tacks, even with the military-type sights!