It's pretty tough to make military actions that were designed around the 30-06 and 7.65 Argentine cartridges to work properly with the 375 H&H and 416 Rem. Mag. cartridges without a lot of work and expense, that is, if you want them to work 100%.

For one thing, the magazine boxes and followers are completely wrong dimensionally and need to be replaced; the magazine box mortises are all wrong and need to be re-machined to accomodate the right boxes, as are the feed rails, extractors, ejector, bolt stop, etc, etc. On top of that 1909 Argentine actions are notoriously soft and need to be properly rehardened or else there's a very real risk of locking-lug setback after just a few rounds.

I'll be honest with you, there's no economy in running with these actions for a 375 H&H or a 416 Rem., and in fact this whole concept represents an exercise in reverse-economy.

You'd be far better off just to pick up a Model 70 375 or 416, and you'll then have a superior action as well that's better-designed and better-built from much better steels that are properly and scientifically heat-treated and is dimensionally correct, by design, to work with those cartridges to begin with. And at the end of the day, you'll have spent less money as well to have this superior product.

Mausers and Springfields might cost less going in, but they cost a whole lot more going out............

PS: Hey 'Vapo', I do indeed go by my real name on these forums; just so you know, and just so there's no mistake.........