modify cz550mag action...

[33HNH]

gentlemen:
i have put together a cz550 mag action (.375 size) with a nice heavy PacNor #6 barrel.  action was trued, bolt lapped and barrel chambered for .404 jeff.  what work will i need to do to the claw, bolt face and/or magazine feed rails to make this sledge hammer feed reliably EVERY TIME!!??  have not tried any dummy rounds yet, so asking about what to look for, watch out for or expect as i head into this unfamiliar territory.
thank you for your input!
greg
salem, oregon

[gunnut69]

My Cartridges of the World is currently missing in action(bookcase moved for placement of wifes curio cabinet) but I seem to remember the 404 Jeffries was a rebated case head design to allow a fairkly heavy large bore slug to be used in a standard 98 mauser length action. Yjis allows a cheaper rifle than a magnum mauser action or a double gun.. It may however produce a problem in the magnum 550 you are using. The 375 uses a large diameter case head.. Of course this is all based on my notoriously rotten memory! If I get my book found I'll look it up.. If case heads are the same diameter the extractor should be happy. I haven't worked with a 550 but assume it's a controled round feed design and that should make a fine rifle indeed. The CZ products I've used have been top notch..

[Nobade]

The Jeff case has a slightly bigger diameter rim than a normal magnum case. You will likely have to open up the bolt face a bit and do some extractor fitting. BUT there's an easier way - just form Jeffrey rounds from Remington Ultra Mag cases. They are based on the Jeff case, but have a rebated rim that is the same size as a normal magnum. Plus you won't have to buy a special shellholder, and the cases are WAY cheaper than Jeffrey cases.

[33HNH]

no way!!!!!!!!  is it really that easy?!  although that seems like a lot of case prep to anneal, open up the neck and resize.  and still, if the case is that much similar i'm going to have to overcome the feed rails. but thanks for the "work around"!! 

of course,... i have all the necessary reloading bits for .404jeff.  since my last post i have made up some dummy rounds.  i can see the bottom edge of the extractor claw needs to be opened up and the bolt face is already large enough diameter so that would take care of the bolt mods.  it's definitely the feed rails that need the work.  as it stands, between the feed ramp and the rails, they push the right hand cartridge to the left where the bullet nose hangs up in the breech.  it also locks underneath the right hand rail and carves an awful gouge in the case.

any "smithy's" out there with some input?  i have seen mr. wiebe's photo montage of "to-do's" and i guess that would be a good place to start but being new to this does not inspire my confidence in the use of a dremel...

greg

[gunnut69]

I'm not any sort of expert but it sounds as if the rails are holding the 404 round a bit too long. If the action was a 375 it is adjusted for a much more tapered cartridge.. The change would be small and to reduce the width of the forward ends of the rails.. This should release the round a bit earlier.. I'm uncertain of your description but that is my 2 cents..

[33HNH]

i think you are right.  i only wish i had current CZ in .404 to measure.  anyone out there have a CZ SAFARI CLASSIC IN .404 JEFFERY?  aside from that i'll just have to learn as i go,... slowly, very slowly...