Well a year after it's conception, the first 600 OK-1built on a CZ550 action( much modified) was fired tonight! It was impressive, but far far away from being the uncontrolable monster we all feared. The cases were homemade Lathe turned brass ( two of mine and one of Fritz 454). The load was 154 grs of Rl-25, behind a 900 gr Bridger brass bullet, Fed 215 primer. The chrono said 1975fps corrected. This pretty much duplicates the old 600 NE load! There will be absolutely no problem exceeding this level of performance.The 360 half-hard brass did just fine as the pressures were intentionally kept to about 29Kpsi. Recoil was reminisent of a 585 NYATI and the brass just popped out of the chamber with absolutely no stickiness. I just finished measuring the brass and it didn't seem to do much of anything. The stock was made by AHR and looks absolutely beautiful. I did all the feeding and ejection work and I think I have this aspect perfected( see the previously posted pictures). The gun will hold two cartridges down and one in the chamber.
The recoil management system of three mercury recoil reducers in the butt ( extremely wide buttstock),F990 pad ,Vias brake and overall weight minus scope of 14 lbs really works! Overall, I'm really pleased at the realization of this project and am looking foreward to the Horneber brass to see what this thing will really do! I hope to post some pictures soon!-Rob

[ 05-29-2003, 09:39: Message edited by: Robgunbuilder ]

Let me be the first to congratulate you, good job Rob.

Good job RGB - concerning the stock, which one are you using? I ask as I am comtemplating the AHR laminated stock specifically for CZ550's on a project rifle - keep us posted on this beast and don't drop it KMule

I cant wait to see the pictures of the .600 OK-1 and it will be fun to hear about the MAX loads
154 grains RL-15 How much powder does the case take as MAX???

Gratulations Robgun !!

I,as OVERKILL wonder now how loaddevelopment will turn out !!
I'm sure it will kick a hell of a lot more, when you turn the charges up a bit with faster powders !!
( I can't wait till we see the first .600-OK2 !)

Good Heavans! A VERY impressive project.. Congratulations on the execution to prediction.

How about some pictures of the complete to shootable cannon?

Glad to hear it turned out for you! Also good that the recoil is managable,launching 900 gr bullets out of a shoulder fired weapon is just cool!

congrats Rob... This project is not over... what next needs to be done?

[ 05-29-2003, 19:43: Message edited by: smallfry ]

What a good job Rob. I'm glad that something like this can come to fruition. You truley are talented,and all of us are lucky to have you around here to dole out advice and help with projects. To think that this started because I was thinking about a .600JDJ and end up as this in this short of time is nothing short of amazing. I just hope that the funds hold out and I can build one in the near future.

Nicely done! I'm anxious to read (and see) about the furthering developments in the world of the .600's

BMG

Well done, Rob.

I'm sure Axel will be around shortly to top yoou with one of his "creations"

One thing now is for sure, and that is that the .600 OK is a far better cartridge and fit with the CZ550/602 than the 585 NYATI will ever be. This is definately the cartridge to have! It can be down loaded to 1400fps levels and up to 2400 fps levels just by choice of powders. A complete gun should be easily producable for about $2500-$3000. I should also compliment JR as it was his thread on the .600JDJ that got me thinking of a belted .600 NE in the first place. -Rob

[ 05-30-2003, 00:27: Message edited by: Robgunbuilder ]

RGB !!

I also wonder what action the .600OK-2 will fit on, and if 2600 fps is realistic....(or should i be more patient?)

The .600 Ok-2 will definately fit into a Granite Mountain action! It will hold three down and feed perfectly. The mag box will hold a cartridge over 3.900 in length. That I can assure you!-Rob

Robgunbuilder, what are the magazine box dimensional differences between the CZ550 and the Granite Mountain Arms?

Thanks,
Axel

Axel- The GMA mag box outside dimensions are 1.209w, 1.954 deep nearest the triggerguard, 1.102w,1.727 deep in the front and 4.096 long. I don't have the CZ box dimensions here with me. Blackburn made the GMA box and triggerguard.-Rob

Hi Rob:

Geez..... great job, your killing me with the suspence....Please post pictures...soooooon..

Regards.. Jim P.

Congratulations Rob,
It's nice to see something go from the idea stage to the finished product. You've solved some real gunsmithing problems along the way and must be congratulated on a fine project. I'm also really looking forward to the photos.
Take care,
Dave

Fantastic!

Now for the Granite Mountain version. Will that one hold 3 or 4 down? I wonder how extreme the mag box would need to be to hold 4 down.

500 grains- Looks to me like the GMA action with a dropped floorplate would hold 4, 600 OK-2's down. Fritz 454 could probably make them for us. -Rob

Robgunbuilder- Congratulations. You appear to be the most talented guy on this entire site! I've seen the pics of your work and it's as good or better than most of the custom gun builders out there. I never would have believed that your .600 OK could actually be made to work. Your even capable of making your own brass that will handle full power 600 NE loads! Man my hats off to you! I can't wait for the pictures.

WWWWWWWWWOOOOOOOOOHHHHHHHHHHHHOOOOOOO
GO ROB!!!!!!!!!
WE NEED PICS SOON. THE SUSPENSE IS KILLING US ALL!
Andy