Winchester and the .300 Win.Mag

I’m writing an article about the .300 Winchester Magnum for a sporting magazine, so I have been reading old American Rifleman and Winchester catalogs (1965).
For what I’m reading it looks like Winchester have not much interest in promoting his new cartridge. At least they are more interested in the other magnums, .458, .338 and .264.
Am I right?

I assume you mean Winchester’s interest in 1965 (the .300 WM actually came out in 1963), and not interest at a later period. I can’t say what Winchester’s interest in promoting it was in 1963 or 1965, but there were several other popular .300 Magnum-level cartridges already on the market (.300 H&H, .300 Weatherby, .308 Norma Magnum), plus some wildcats, at the time of its arrival, so the .300 WM was not exactly a new and revolutionary idea, nor did it fill a need not already met by one or more of the existing .300 Magnum cartridges. Winchester as an organization was going through considerable financial turmoil at that time, and I imagine their management’s interest was much more heavily directed toward corporate survival than in the .300 WM (or any other caliber). As a result, Winchester prostituted virtually their entire line of firearms, resulting in the current collector interest in “pre-1964” Winchester rifles and shotguns, as their quality level was seen as being superior to post-1963 products (rightly or wrongly). Others here may be able to address Winchester’s attitude specifically toward the .300 WM at the time, but I cannot.

You should also include a mention of the military version of the .300 Winchester Magnum, the Mk 248 Mod 1, for use in the M24 sniper rifle, as that is a fairly new development.

Thanks Dennis,
I have some American Rifleman fron 1964 and there is no mention about the .300WM other than a short article mostly a hunting report.
On the other hand, there is a full back cover advertice of the .458 WM and a long arcticle about the development of the 264 WM.
Thank you very much, I include the Mk 248 and a mention on the rebarreling of M24s for the .300WM.
Thanks again.