Well- I spent the weekend working up loads for the 600 Ok-1 and I'm still here to tell about it. Using the Lathe Turned Brass, I was carefull to try and keep the pressures to about 32 Kpsi. I settled on a load of 155 grs of IMR 7828 with a 900 Gr Woodleigh for 1950 fps over the Oehler Chrono. The recoil system on this gun works superbly and given these loads duplicate the 600 NE, I have to say it's a pussycat to shoot!!!. Exceedingly accurate offhand at 50 yrds and very little muzzel flash. The CZ550 action feeds and ejects the 600 OK cases beautifully( so much for all that crap about the slighly rebatted rim not feeding) and I would not hesitate a minute to take this rig to Africa for ELE it';s that good!
By the way, the Lathe turned brass holds exactly 210.5 grs of water and at these pressures just pop out of the action with no sign of stickiness at all. I've fired about 40 rds this weekend and in the end became comfortable enough to even mount a scope.! I think the 600 Overkill is a tremendous success story! Once the Horneber Brass arrives, it will be easy to crank up the power on this beast! Here are some pics!

Here are some loaded rounds of 600 OK-1,505 Gibbs,500 AHR and 470 MBOGO for comparison.

In case anybody thinks I'm exagerating about the offhand accuracy here is a target from 50 yrds with 2 600OK-1s touching and 3 470 MBOGO's

The stock is very nice with three mercury recoil reducers in the butt and the F990 pad.

Here is a picture of the Vias Muzzel brake!

Here is a picture of the three groove rifling in the barrel. This seems to help lower the pressures also and may give some higher velocities. It certainly DOESN'T hurt Accuracy!!!

Finally a picture of my latest 470 MBOGO! I posted this one awhile ago when it was unfinished. It was checkered by AHR as was the 600 OK. This gun also shoots as good as it looks!-Rob


[ 06-02-2003, 18:59: Message edited by: Robgunbuilder ]

It sounds as if the 600 OK about maximises the power available for a "rifle"

An obvious added plus is that due to recoil limitations pressure remains within the bounds of lathe truned brass.

With flat nose cast bullets it would be unreal on roos in the spotlight, definitely better than the 460 Pure lead paper patch would be interesting to say the least.

Mike

Rob,
Great work mate. what is the barrel length of the rifle?
The 620 club has begun.

Karl.

It sounds like a great success.

At 1950 fps, would you say recoil is in the 585 nyati range, or is it a bet less due to the low velocity?

Also, how badly battered do the soft points get in the magazine?

Thanks for the update and the pictures!

500 grains- recoil is actually Mild as compared to the 585 NYATI. I think I have a much improved recoil reduction system now as compared to before. The crimp on the cases is very strong and the bullets are seated on top of a near compressed load, so I didn't notice much damage to the bullet nose. The barrel is also 26 inches long with what is left of an 11 degree crown at the muzzel! The muzzel is thraded with a 7/8 X 24 TPI thread so its getting pretty thin out there. -Rob

Looks good Rob!
I'll be eagerly awaiting my brass when it get's here and will definately be watching/reading the current 600OK updates.

Great looking rifle, you do top shelf work.

Do you anneal the lathe turned brass after every 2-3rd shot? My .577 Snyder lathe turned brass lasts a long time when I anneal the cases, but tends to split after 7-8 fireings with no annealing. The lathe turned brass also 'becomes' more like drawn brass cases with repeated annealing after 2-3 shots. The HH drawn brass will allow greater 'recoil awareness' in the future

RGB!

What a nice rifle... I want one.. but I have to save money first. What was the price of a rifle in .600 OK??? will the .600 OK-2 cost more?
When are you going to test harder loads?

Very nice Rob!

Thanks for the pics. Very impressive indeed.

Cheers,
Canuck

Congratulations!! From start to finish, you've done a hell of a fine job. Great looking rifle. I hope the Horneber brass arrives soon.

FWIW- There is a Heym 600 NE bolt action for sale on Gunbroker starting at $8500. 2 shots and crude as hell!
You could have a 600 OK-1 with a nice piece of wood built on a Granite Mountain action for literally half of that!-
I'd say the rifle shown here on a CZ550 could be easily built for $3500-Rob

Hot Dang it, Rob! My that's a big one!
Great looking rifle that shoot well!
Where did you get the stock? Beautiful! I'm looking for one for my 404 Jeffery.

Rusty
We band of brothers!

[ 06-03-2003, 03:37: Message edited by: Rusty ]

Rusty- AHR can make you a complete stock for your 404 project! Give ED a call tell him you want one just like on the 600 OK!!-Rob

Hi Rob,
Very nice job on both rifles. They are both awesome and like you mentioned they both shoot as well as they look. You do have to take a lot of the credit in the shooting department though. I think your idea of building DGR's after you retire would work well for you. The customer would be assured of a good product.
Take care,
Dave

Nice rifles.
Have you fired the rifle without the muzzle break? I am curious how effective a brake is at Nitro Express velocities and pressures. I may have missed it, but how much does the rifle weigh?

Rob,

Have you shot it without the brake yet?

What was that like?

Thanks.

Rob,

Is the $3,500 all in, with gunsmithing services included? Looks nice...

Could you explain how you made the brass?

Mike

Rob

You da man!!

Nice nice nice.
If I lived in the USA you would keep me broke!

Did you have to modify the Vais? I noticed that some of the holes appear to be connected.

That's some first class shooting too!

Do you know anyone that is good with big bores in Canada?

The brass is pretty easy to make. I have a manual Sharpe Toolroom Lathe with DRO that I use for this! You start with .750, 360 Half-hard brass rod and turn it to about .700 on centers. It's then progressively drilled starting with a .500, 9/16 and finally a .600 drill. I typically use drills with Morse taper shanks for rigidity. You then ream the brass to a depth of 2.740 with a .620 reamer. You can also use a good carbide boring bar for this operation! Brass likes speeds of around 800 rpm for a good surface finish. I then insert a homemade .619 mandrel into the hole and support the brass between centers again. Now the outside is turned to the final case dimensions.655 ( at the case mouth) up to the belt(.658). I put in a slight taper while doing this step. I then cut the belt to .682(.094 wide). I've made a custom tool out of a carbide cut-off tool that makes the extractor cut,shapes the back of the belt and cuts the back of the rim all in one pass. I then part off the case. You then re- chuck up the head of the case and with the DRO and tool positioned properly, face the case till its .260 from the case head to the front of the belt, then turn the rim down to .640. Chamfer the rim at 45 Degrees and make sure it's .055 thick. .260 is the critical headspace distance. The chamfer is critical for smooth feeding! You then drill the primer pocket and ream to depth. The case will be 3.00 inches long. Once you get the hang of it, and find the right speeds, it goes really fast. Of course the real answer is a CNC Lathe like Fritz 454 has .-Rob

[ 06-03-2003, 10:51: Message edited by: Robgunbuilder ]

Thanks Rob that is just too cool!

Mike

Rob
Very nice! I hope I can do 1/2 as nice of a job as you in the future. I know where there is and elephant that needs to be shot in september! That cannon just might do the job.
Dean

That thing looks great Rob. I can't believe everything is already done!
One question: Where did you get the barrel swivel at? I have been looking for one to put on mine but can't find any.

The barrel swivel is from NECG. It's also soldered on! Given the diameter of the barrel, you can't screw anything on and I didn't even try to make a barrel band.-Rob

Robgunbuilder,

All I can say is wow. What an accomplishment. We need some video of that thing being shot and vaporizing some stuff!

--QD

Pretty cool Rob! I will never doubt the effectivness of a good muzle brake on a stomper! Makes em fun to shoot! Get us some pics of that rifle vaporizing some water jugs! My 577 is pretty impressive on jugs full of water,I get two gallon size oil jugs from work.I will post some pics later on!

Rob,

that is a great looking rifle in a couple of years I would like to build one to compliment my other big bores !!

Great piece of wood to.

Congrats you must be happy.

Need a test shooter???

Great looking rifles, Rob.

s