Well I just received my CZ550 action and will open up the bolt face tonight to about .640. This will not leave much meat on the bolt, but I'm assured it will be enough. I suppose I'll find out the hard way. If anyone out there has built a Nyati on this action, I'd appreciate any info/techynique used for opening-up the rails to feed the cartridge and/or if any ramp work is needed to assure proper feeding.-Rob
I've talked to some folks who have had to make single stack magazines for this cartridge and I hope this will not ne necessary.-Rob

Rob,

Would the single stack allow full reliability when the 585 Nyati cases have the 416 Rigby rim diameter.

Mike

Robgunbuilder
Take a look at what I wrote when you asked for best action for the 585.

With a cross feed magazine whats left on the bolt after opening it up to .640 will (from, my experience ,brake off...)

I have not tryied a singel stack with a .640 bolt face ...that might very well work?!?!

Shadrek

Shadrek- I read your post and I have to admit it caused me re-think this project. However, after some discussion with some machinist friends, I opened my bolt last night to .639 and I have about .030 left on either side. From your post it appears you went to .660 which I agree would leave only about .020 of rim which might shear off. Now that I have done the machine work the bolt appears just fine and I have talked to others who have done this with no problems. Ed Plummer at AHR told me that they are opening their CZ550 bolts to .640 in their 585 AHR's in order to use the Bertram brass which is .635 at the rim. Having to turn down the Bertram brass just isn't that appealing to me and might force me to a single stack mag which I am trying to avoid.
Interestingly, I looked at another 585 that was built with the opriginal.590 i.e..416 Rigby boltface. It required a Schuler type single stack magazine to feed properly. I was concerned that by rebating the Bertram brass to .590 that in a staggered magazine that this would lead to feeding problems with the bolt over-riding the severely rebated rim. While I personally have never tried this, I've been warned by others that this could be a problem.
Since you have opened-up your Magazine rails, I wonder what dimensions you used and if you ran into any problems with the feed ramp? How smootly does your 585 feed?-Rob

Rob,

My 585 is a Win model 70 with a Shuler style single stack. I have .640 rims on my cases and the feeding is flawless.

However, I have a CZ550 action and a spare .585 nyati barrel in the safe ready to go. Please let us know how this goes, because I do not want to be a pioneer with the CZ as I was with the model 70.

Also, did you talk to Dennis Olsen and has he made 585's on the CZ action? Does he prefer single stack or staggered feed for the 585?

500 grains- Where did you get your Schuler mag? If I had one, I'd definately go that way and use the .416-(.590) boltface. Unfortuately, you would have to rebate the brass, but the single stack would assure proper feeding. It just seems better engineered to me. With that said other than Shadrek no one else reports problems with the
thin .640 boltface of the "standard" Nyati.
I talked to Dennis Olson and he seems fine with the staggered Magazine as does Pac-Nor and AHR. Unless I can find a Schuler type Magazine which fits the CZ action, this will be the way I'll go. -Rob