Is there any readily available caliber out there to buy in a CRF action that could be changed out to .404 Jeffery easily? Is it possible to rechamber one of the 416's, rebore and rechamber , or, say, add a new barrel to a .458? Just looking for a relatively inexpensive way to get into one, probably starting with a gun with a Zastavia or Mauser action or some such? I am a newbie to build your owns...as I am sure my questions prove. Any info would be appreciated.
thanks
Rick

Issue you will have with a rebore is insuring the longer shallow tapered shoulder of the 404 would clean up the old chamber.

As to the Zastavia the cheapest way to get that action would be a Rem 798 in 375 or one of the later non Whitworth MKxs or Daly in 375 that way the major cost would be covered. Have a 404 barrel installed.

Another option is the M70 even on the short action it is a quick fix to remove the spacer and lengthen the box.

Buy a CZ either in a long magnum and swap the barrel.

Not sure if any of these options will save you that much $$$ over just buying a CZ in 404.

Check in Big Bores forum, several of us have had Win M70 Classics that began life as Ultramags rebarreled into 404's. Mine was a 300 RUM that went off to PacNor for a rebarreling.

Once the open sights were added, I think I only saved about $500 from getting a CZ, but the other rifles I use are Win M70's and I wanted to keep things the same from gun to gun.