Not quite right. The magazine well in the M1999 receiver is 3.730 wall to wall internal dimensions. With the long magazine (there are two variants) box wall thickness of nominal .040 (stainless 304 and .036 by my measure), the internal dimension comes out at 3.650in usable. Say 3.625 for max reliable feed COAL length. Obviously fine for the .375 H&H and its ilk. Two other boxes have .250 spacers inserted (3.40in internal) for .300win and 30-06 type cartridges.

We use the CCRM-U (ultramag) configuration for .404 Jeffries. This box has clearance windows, is 3.650in internal, and has a wide-tray follower for the .550 case bodies of Dakota, Ultramag, and Jeffries. Our barrels (we have several uncontoured blanks in stock for Jeffries) use the .424 groove diameter. Some people want .423. Doesn't matter to us and doesn't seem to matter to the rifle.

Call Larry at 406-756-2399 for more info.

Yes, it can if you can find a "long action"..the 1999 is not a long action, it is a 06 length action that can be opened up to 375 length as I understand it...They are supposed to make a long action but I have yet to see it..Perhaps CZ will get them as they are now using Montana action I understand.

If you can get one, then you will have the problem of finding a 404 box that will work in them...They will tell you a 416 box is fine, but that is wrong, the stack is improper with the 416 box...

I went through all this mess and ended up peddling the Montana action, which didn't suit me for several reasons, not the least of which is the hole in the front ring is located too low and would blow the wood out on a properly stocked rifle! thats a really stupid mistake in design IMO..

I built my last 404 on a CZ 550...It was fine, but I still think a 404 should be built on a Mod. 98 Mauser action with a good drop box magazine...

Just my opinnion.

Can a 404 Jeffery be built on a Montana 1999 long magnum action ?

Hammer

Ross Seyfried originally designed the .585 Nyati to work in an m98 which it will....in a pinch. Poster 500 gr also had a .585 Nyati on an M70 winchester originally it was a .375 H&H I think. My .585 is done on a 602 Brno, which I feel is the limits of that action as well. Good news is Montana is building there PH actions which will have .750" bolt diamters which will solve a lot of issues for those wanting to buil .585's.

Thank you, Serengeti.

I have a left-hand Montana 1999 stainless-steel long magnum action originally ordered for a 375 H&H. I have an UltraMag magazine box and follower already on the way.

Further question... Can you build a 585 Nyati on the Montana action ? Have a few of the lefties put away for projects.

Look forward to talking with ya'll.

Hammer