Have been lurking here for a while and reading this and other threads about special order model 54’s and 70’s in rare non-catalogued calibers.

Doing a little research on the auction guns trying to figure out the barrel source.

How would Winchester accommodate requests for a non standard barrel caliber? Thinking they would produce the closest cataloged barrel, refine it further, then proof fire. Wouldn’t Winchester want to test a non-cataloged caliber before selling one to a customer?

Appreciate any insight, going to see what Rule has to say since I rarely if ever look in the special order section.

Noticed the Model 54 carbines has swivels.

Louis Luttrell said
Hi mfivefour-

A few thoughts on barrel specifications for chamberings that are rare and/or uncataloged in the M54/70.  Some rare M70 chamberings were cataloged M54 chamberings, e.g. 30 WCF, 7.65 M/M, and 9 M/M.  So they had developed barrel specifications for those.  In fact, the 7.65 M/M and 9 M/M M54s were made after 1932, so they even had M54/70 pattern CMS barrel blanks in those calibers that could be repurposed to build a M70 if so ordered.  The 30 WCF, even on M70s I’ve seen that I believe genuine, used a different rate of twist and a flat breech system, so those barrels had to have been made special.

Other rare (or non-existent, depending on your point of view) calibers in the M70 were chambered in other Winchester models, e.g. 348 WCF (M71) and 405 WCF (M95).  So M70 pattern barrels would have to be made special, but the barrel specifications were known, so no R&D/testing would be needed before filling an order.

Still other possible chamberings, e.g. 280 Ross, 303 British, had been developed elsewhere.  But given that WRACo. and Winchester-Western manufactured ammunition as well as firearms, they no doubt had velocity/pressure/accuracy barrels for a great many cartridges that they didn’t routinely offer in rifles (or even load commercially).  After the M70 came along, M70 receivers were the test bed for ammunition development.  So again, they likely already had established barrel specs for a multitude of obscure chamberings.  For interest, below are a couple photos I got from Justin Hale (pre64win.com) of a tool room M70 test barrel in 303 British that he ran across during a recent trip to Montana.  This is not a rifle, just a test barrel with hand stamped caliber designation.  But note the way the breech was machined to handle the rimmed cartridge:

OTOH, engineering the M70 action to feed/fire/extract some of these cartridges using adaptations of existing magazine/follower/extractor, would have likely taken some fiddling on a case-by-case basis, which is one thing that makes some weird chamberings less plausible than others.  But if you could make a M70 work with the 30 WCF family of cartridges, I suppose you could make it work with just about anything.

Hope this helps

Lou  

Thanks Lou, very informative info as always.