... I was asking about why the reference you cited calls the [Lee Navy] case "semi-rimmed," because it isn't, any more than the 30-06. ...
MD-
The specs noted by Swifty52 appear to have come from the "specifications" sidebar in the Wikipedia entry on the 6mm Lee Navy:
[color:#0000FF]Wikipedia entry (dated 02Sep13)[/color]I've found some further information on the rimmed version of the 6mm/236 Lee case.
C.V. Hamilton's short 1962 book,
U.S. Metallic Centerfire Rifle Cartridges 1860-1960, describes both cases. For the
rimless version, rim diameter is 0.446" and body diameter is 0.445". For the
rimmed version, rim diameter 0.515" and body diameter is 0.448". Hamilton's measurements are based on actual specimens. The drawing of the rimmed cartridge shows no extractor groove in front of the rim. He has labeled the rimmed version as "236 USN for Blake Rifle".
Sharpe's book,
The Rifle in America, mentions the rimmed version in two places. Discussing the Lee Straight Pull rifle (p.236), he notes his sample rimmed case has a .236 USN headstamp. Sharpe states a hypothesis that the rimmed version was intended for experimental use with the Army's Krag rifle, although he notes he has no factual basis for this. Sharpe's assumption is probably incorrect. The Krag cartridge has a rim diameter of 0.545", so a rim of 0.515" is likely too small. I think the histories of the Lee Navy cartridge make it clear that the Navy was acting very independently of the Army in the 1890s in selecting arms.
Sharpe's second mention of the rimmed version is found in a description of the Blake rifle (p.106,111-112). John H. Blake had presented a military model of his rifle to the 1895 Navy rifle selection Board, but an untimely illness prevented him from adapting it to the Lee Navy cartridge, which had already been developed and selected. The Board did say nice things about the Blake rifle.
A few Blake sporting rifles may have been chambered for the rimmed version of the Navy cartridge. A Blake catalog described the rimmed cartridge as firing a 135-grain bullet at 2500 fps; the standard rimless version used a 117-grain bullet at 2800 fps.
A discussion of the Navy cartridge on a 2012 thread in the IAA forum,
[color:#0000FF].236 U.S.N. cartridge by WRA[/color], provides some further information from knowledgeable individuals. The shoulder shapes of the rimmed and rimless versions differed somewhat, and its possible to find samples of rimmed and rimless cases with shoulders of both types. As a result, there are four different case shapes for the Lee Navy cartridge. Obviously, the most common by far is the rimless cartridge issued to marines and sailors; the other three are rare.
Is there an industry standard definition of the term "semi-rimless", or is the term generally descriptive with fuzzy edges?
--Bob
