243 win intro

I’m considering a short JOURNAL article on the lowly, common, 243 Winchester. I know - how ordinary and boring! But, there’s more to it than meets the eye.

Anyway, do any of you have anything that will pin down the introduction date. By that, I mean something more detailed than “1955”.



Ray - I have pretty decent Winchester files, but after one hour of searching, I could come up with very little other than “1955” for the introduction of the cartridge.

One thing I can offer is that the barrel caliber-marking die for the winchester Model 70 in .243 winchester caliber was die number 33933-1395, and that it was authorized on February 17, 1955.

another is a factory drawing with a date of October 6, 1954. That drawing has additions up to October 1961. It is interesting that there is an entry dated May 15, 1955 on the drawing that indicates “243 WIN. was 6 MM WIN” with no other explanation. The only thing puzzling about that entry, the first revision to the 1954 drawing, is that it came so late. It would seem to indicate, at least to me, that the cartridge was actually offered to the public after May 15, 1955, but that doesn’t wash well with the normal publishing dates of catalogs in that era, which were around the first part of the year. The Winchester 1955 catalog does show the Model 70 and Model 88 rifles, the latter introduced in 1955 as well, in .243 caliber.

I was disappointed that SAAMI has no such nformation. They don’t even date their drawings, at least in the published form. I have the SAAMI Drawings.

I cannot come up with any specific date in 1955 other than this. Sorry to give such scant information. I have to go for my haircut appointment, but if I have any time when I get back, I will look a little more. I think, though, that I have hit any source I have likely to have this info. Aside from factory material, I had a couple of dozen articles on this caliber - all just give the 1955 date - and four articles on “Dates of Introduction” of cartridges, none of which give more than the year - again, 1955 for the .243. It is obvious that to be authorizing the manufacture of a barrel-marking die in mid-February of 1955, that development of this cartridge had to start in 1954 at least. As you know, these things don’t happen over-night in factories. ots of R&D, Market survey, tool and die making for cartridge production, test firing, establishment of proof loads, etc to be done before a cartridge/rifle combination is introduced.

Reference: “The Rifleman’s Rifle,” by Roger C. Rule, page 112
"Winchester Chamber Drawings & Cartridge Drawings 1928- 1962, Gig Publications.


The original prototype rifles were marked 6mm Winchester and there are cartridges with that headstamp. From your references it would appear that the change to 243 Winchester was authorized and took place sometime around or after May 15 and lacking anything more precise that is probably as good a date as any.

Development of the cartridge started much ealier than that, possibly as early as 1952 and no later than early 1953 I’m sure. Both Winchester and Remington were considering a 6mm cartridge at the time but it took two wildcatters to push them to a final decision. But, I’m giving my story away . . .

Thanks for all your time and effort. You have helped a lot.


Ray - the problem I have with dating the cartridge from May 1955 and the name change from 6mm to .243 at that time is that the barrel-stamping die with the desgination .243 was already approved in February 1955, 3 months earlier.


Good point. I re-read your post and now think that placing the introduction as “early 1955” might be more accurate (and safer).


Ray and John…This is from the draftsman’s point of view…sometimes, with the draftsmen at a firm occupied with more important things, like new design, for example, drawings requiring changes can sit around awhile before someone gets around to changing them…even if the change has already been incorporated on the factory floor…so going by dates on drawings when changes were made may not always lead to correct conclusions…Randy