6mm USN - ? date of manufacture

I know that the history of this cartridge dates back to the late 1800s but I am wondering if anyone can give me a period in which WRA Co made them? I know Winchester produced the early ones with the headstamp W.R.A.Co. .236 U.S.N but when did they change this to the metric designation?

According to my data base:

The 6mm U.S. Navy or 6mm Lee Navy (Rimless) cartridge, (aka .236 Navy) was used in the U.S. Navy from 1895 to app.1907 in the Lee Straight-Pull Rifle and Colt Mark I machine gun and Gatling gun. ( There was a rimmed version used in Navy tests in 1893 but it was not adopted by the U.S. Military)
The Military cartridge was manufactured by W.R.A.Co. and U.M.C. Company for the Navy.

Later Winchester, Remington and Blake chambered the caliber in sporting rifles and sporting ammunition was manufactured until app. 1935.

Again from my data base, other data my be different or be able to add more information.

Thanks Dave - I wasn’t sure when the metric designation would have been used. I’m sure it is covered in HWS Vol I but I a friend has borrowed it, so I cannot look.

I was told not many were produced so I grabbed it. If nothing else, it fills a gap in the timline between the .45-70 and .30-40 Krag rounds in my collection.

The .236 & the 6mm are found in the maker(s) headstamps & case types.
The .236 was a rimmed cartridge but you will find that headstamp on rimless and the 6mm was a rimless but you will find it on rimmed cases. You need to study both UMC & WRACo product to find these differences. Also the longer .236 shoulder is found on rimless cases.
This shoulder ‘movement’ is a bit of a mystery. Bill W. thought it was a factor worth of mention, but Frank H. did not.

Pete, the rimmed must be rare ? Were they not only used in 1893 test or trials, my Hoyem book read 500 made ? I have no idea.

From IAA issue 526, March / April 2019 page 52, the Cartridge Prices. To my mind these are a little low, but answer your question as to rarity.

Not that interested in a price list.
Interested in the rimmed 6mm production in the late 1890s.
There is a lot of rimless out there. not sure of the rimmed.

I paid US$3.50 for mine, so for once I had a win!


The .236 U.S.N. and 6mm U.S.N. are not actually synonymous. The .236 is rimmed with a 135 grain bullet, whereas the 6mm U.S.N. is rimless and uses a 112 grain bullet. Usually. Then there are the military loadings and the civilian loadings. Then there are the exceptions.

According to HWS Vol. - 1 the .236 (6mm) U.S. Navy round started with the Navy’s approval of the preliminary design for the cartridge on October 18, 1893 by the Bureau of Ordinance. The cartridge design called for a a 135 grain bullet with steel full metal jacket with lead core and cartridge case to be rimmed with a bottleneck case, measuring ~2.345 to 2.35 inches. Rim diameter was 0.517 inches. The final design was approved by the Navy on December 27, 1893. The final dimensions on the cartridge were a rim diameter of 0.513 inches, head diameter of 0.445 inches, neck diameter of 0.268 inches, bullet diameter 0.240 inches, case length 2.35 inches, overall length 3.18 inches. December 1893 marked the first production of the USN Cal. 0.236 ball cartridge and was headstamped W.R.CO. .236 U.S.N.

The initial lot of loaded ammunition was 5,000 rounds ordered in March, 1894. Apparently, Winchester was offering these cartridges to the public almost simultaneously as they were advertised in their catalog 53 dated November 1894 and were headstamped W.R.CO. .236 U.S.N…

According to HWS, the last date of manufacture took place during and shortly after March 1895 by Winchester for machine gun testing. Also some .236 cartridges were also ordered from U.M.C. at the same time for machine gun testing. HSW noted some variation in the style of the headstamp. Rounds may have the 6mm U.S.N. headstamp, which is normally used on the rimless case and has small lettering.

HWS point out that about in March 1894, the Navy Bureau of Ordinance refer to this cartridge (.236 U.S.N.) as the U.S.N. 6mm while Winchester still calls it the Cal. .236 U.S.N. HWS summarize the brief chapter with two cartridge listings: (1) Cal. .236 U.S.N. which is the rimmed version with 135 grain bullet 09/22/1893; and the (2) 6mm (Cal .236) (W.R.A.Co. Drg, 5103, Form No.3) with 112 grain bullet 02/1896.

I am sure you will see this topic can be very confusing, but that is part of the fun right? However, the history and nomenclature become relevant when talking about this cartridge.

I have in my collection one of the rarer cartridges mentioned above. It is the .236 U.S.N. cartridge with the headstamp U.M.C. 6mm U.S.N. By convention at the time, it should have been U.M.C. .236 U.S.N. I am no expert and what I know comes from HWS, but my best guess is that it was manufactured close to the time when the Navy first ordered cartridges from UMC in 1895 before they caught on to the nomenclature. If anyone has better information I would appreciate hearing it. In my experience the value listed above by Pete is at least an order of magnitude lower than what I experienced 10 to 12 years ago and 2 to 3 times lower for the other types of 6mm U.S.N.

Additionally, in my collection there is a W.R.A.CO. 6mm U.S.N. paper bulleted blank (circa 1897) of which 100,000 were ordered from both Winchester and UMC, the order split in half between the two.

Also a gallery practice U.M.C. 6mm U.S.N. with 80 grain bullet is in my collection. It is circa 1897. No idea as to number manufactured.If anyone knows, please advise.

I have various commercial headstamped 6mm U.S.N. and Navy variations on tinned bullets and primer inscriptions.

Probably 30% of the 6mm U.S.N. cartridges that have been in my hands have split necks probably from the metallurgy of the time. All the .236 and 6mm U.S.N have corrosive primers and you will find brass, copper, and nickel primers crimped and uncrimped.




heavyiron1, Thank you for the information
Yes some what confusing, had to read it a few times. But that makes the study more interesting.
It appears the rimmed version was only in a trials ? Making it far less available then the rimless cartridges?
Yes split necks is an issue on a many older bottle-necked cases. Brass does get brittle, like us old people :-)

Glad to see you agree with me on the prices, being low. Sorry I can’t help with your question of the time of this round, but think your thoughts are probably correct. Nor can I help with the numbers of gallery rounds being made.
I do think that any round found with a NICKELED primer is not factory, as the firearms were later sold to the public as was the ammunition.
Also numerous dummies were made in both rimmed & rimless by both UMC & WRACo.

You stated you were interested in the rimmed being rare, you did not state the 6mm rimmed headstamp, why I replied with the price list. Any by the way, in which volume of Hoyem are these mentioned?

To my mind the 6mm rimmed with the 6mm USN headstamp & shoulder is a xx-xx dollar cartridge, so not so rare but definitely one of the better examples. Note this, in the photo below has the 6mm shoulder. As I tried to point out before the headstamped .236 is also is found rimmed and with a 6mm shoulder
Also I think this below headstamp-size bunter was also used to manufacture the rimless 6mm Lee Navy. So that further cements the above thoughts of Heavyiron as to the timing.

Edited to remove the price as I see some one sold a $15.00, UMC .236 round to an unsuspecting buyer on gunbroker for the price I had listed.

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Now I am definitely confused. You are talking about rimmed and rimless, and Wikipedia is talking about semi-rimmed.

Only two variations i know of are either rimmed or rimless. I’d guess someone at Wikipedia can’t tell the difference between rimless & semi-rimmed.

Read Hackley not something written by ???


Ammo One
Dave I cannot answer your question as to the rarity of the rimmed .236 USN. HWS accounted for approximately 36,000 rounds in total: 1000 were primed empties to be handloaded at the rifle trials in Maryland, a 5000 round initial order and final order for 30,000 rounds for machine gun testing. Apparently, there is no complete listing of orders. It seems there should be more production. I didn’t mention it yesterday because the subject was 6mm USN ammunition, but I also have several .236 USN rounds in my collection all with UMC headstamps. One has a soft point bullet (which must a commercial issue by UMC) in a .236 USN rimmed case, another is a tinned FMJ bullet in a rimmed .236 USN case, another has a cupro nickel bullet in a rimmed .236 USN case, and the final one is a dummy round with a FMJ cupro nickel steel jacketed bullet in a rimless .236 USN case. Go figure. It appears that there are a variety of bullet types that were manufactured but not necessarily fully accounted for in the Navy ordnance records. More might have been produced than the documentation indicates, but the existing supply still seems small.

sksvlad, I read the same piece on Wikipedia and said to myself “What?”. Obviously, the author never saw any of these cartridges. Their source list and reference list were creditable though, I think they just did not understand the terminology.

Pete, the headstamp font on the 6mm USN rimmed cartridge in my collection looks identical to the one you picture and is also illustrated in HWS. The dummy round definitely provides evidence that UMC produced a rimless .236 USN casing at some point, although why and how many are unknown.



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I have seen numerous times the 6mm Lee Navy described as semi-rimmed in gun magazine articles. I believe this is due to the fact that it is considered the parent case of the .220 Swift (which is semi-rimmed). Winchester made the Swift semi-rimmed to allow the use of a bolt face for .473" dia. rims as found on the .30-06 Springfield and other popular calibers. Simple measurements show that common 6mm Lee Navy case is rimless as do the dimensions shown in the Widipedia article (a .003" larger than base dia. rim does not a semi-rimmed make!)


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James Paris Lee held numerous firearms related patents, including of course those related to the Winchester Model 1895 6mm Navy straight pull rifle design. There are prototypes made in other calibers, but I don’t have details on those.

One of Lee’s patents (US 378255 of February 21, 1888) “Cartridge for Firearms” precisely relates to the 6mm US cartridges.

In it, he noted the problems with rimmed cartridges feeding from magazines, box magazines having been one of Lee’s pioneering inventions. He also noted that the rimmed (“flanged”) cartridges had that feature for the extractor to engage. He went on to note that rimless cartridges used a groove for the extractor to engage.

His patent was for the use of a very slight rim (“say one one-hundredth of an inch in an ordinary rifle cartridge beyond the [base diameter]”) for headspacing purposes, and a groove for extraction, and also a slight bevel on the rear corner of the rim to allow cartridges to feed without the entanglements common in rimmed ammunition.

Full text of the patent with all drawings can be found at

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Pete and Gregory thank you for the picture and info