WRACo 6 mm USN with experimental primer

General Ammunition Discussion
#1

The previous thread on the .236 USN reminds me of a recent find in this caliber. It looks like a normal ball loading with a tinned copper jacketed 112 gr. bullet but it bears a ringed oval brass primer stamped with a “O” in the center.

WRACO Volume II p. 191 says: “Smokeless powder ledger indicates ‘Change lenght of primer cup 6 m/m and all similar. Cup (6 m/m) is now tinned & has no ring’ 9/22/98. (Author’s note: The mention of a ring in the first segment is a circle marking on the cup which was used to denote experimental. This does not refer to a ring crimp.)”.

An empty primed case using this primer and with a deep cannelure on the neck is also mentioned in “History of Modern U.S. Military Small Arms Ammunition, Volume I” p. 47.

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Primer Markings
#2

This same primer can also be found loaded in .30 Army cartridges with headstamp W.R.A.Co. 30 U.S.G.

Randy

#3

Is this primer similar to Winchester’s protected primer in having a sleeve around the cup? I ask the question because the quote “cup (6 m/m)” could refer either to caliber of the cartridge or, possibly, diameter of the primer. The Winchester 5-1/2 primer had a diameter of .236 in. Jack

#4

Jack, this primer is a WRACo No. 2 1/2 W of .210" diameter (when crimped measures .193") and It is not protected. The ring diameter impression is wider than the typical W inside a circle.

#5

Fede: Thanks for the response. The very heavy crimp and the bevel at the edge combine to render the proportions of this cartridge slightly difficult to grasp. Jack