Hello everyone, I posted this on a few other forums before I got steered this way. So hopefully there are some people here with 600 Overkills that I can ask a few questions.

My gunsmith and I have just started this build, but have already ordered a CZ 550 magnum action with a 505 Gibbs boltface. The main things I am trying to figure out right now are the barrel length and stock. I'm leaning toward an 18 inch barrel and a McMillan synthetic stock in light tan/brown. I Photoshopped a picture of what this would look like:



And just so you know I'm building this gun just for having fun at the range. Below are some videos of what I use my 460 Weatherby for:

460 Weatherby 1
460 Weatherby 2
460 Weatherby 3

Anyway, any advise or ideas on this build would be appreciated.
Thanks

I'd get Wayne at AHR to build you a stock to fit. with little larger butt and comb-- to make it more comfortable to shoot. If there is any comfort in a 600 Overkill.

Ed

Are you going to use a LH stock on a RH action?

quote:

Are you going to use a LH stock on a RH action?

No, that's just the only picture of the McMillan stock I could find, so I mirrored it to fit the action.

56hawk,
Congratulations on a great choice in calibers. All of us who have taken them to Africa and used them on dangerous game will tell you that they are the Hammer of Thor.
Those of us who have used them on dangerous water bottles, watermellons and charging Cape buffalo targets will say the same.
And those of us who have used them on Prarie dogs will tell you that you are lucky to survive such an attack by these dangerous critters as the 600OK is barely adequate.

Were it my choice, I would not go with 18" barrel and stick with a 22" - 23" barrel. Many would argue for a 26" barrel. I prefer the 22-24" as a compromise between handling and comfort.

There are many people who have used them with varying barrel lengths.

PM SAFARIKID for his view on a 600OK with an 18" barrel. Mind you that he is built like a Terex Titan except Tom (SAFARIKID) is tougher.

PM Michael458 and srose who played with my 600OK built by AHR with a 23" barrel. Michael prefers short barrels himself.

PM Robgunbuilder - the designer of the round and builder of the first bunch of rifles for it. He prefers 26" barrels.

These 4 guys will give you the real-world honest scoop and are people who have used big boomers for DG.

Good luck and congratulations,

Paul

Paul, why would you recommend a 22-23 inch barrel? My main concerns are to keep the weight down and to have a rifle that looks good. As long as I can hit a two liter bottle at 25 yards I'll be happy.

I found a picture of Safarikid's 600 and dropped it in for comparison. With that stock the 18 inch barrel looks pretty long. Seems like his length of pull is kind of short also.

The longer barrel will provide a bit of relief from muzzle blast. I would be concerned about balance, too. Perhaps using a slightly smaller diameter and adding a couple of inches would give a good result. After all, I'm sure this piece is intended primarily to be shot off hand. My biggest caliber is a 458 Lott, so what do I know?

quote:

Originally posted by 56hawk:
Paul, why would you recommend a 22-23 inch barrel? My main concerns are to keep the weight down and to have a rifle that looks good. As long as I can hit a two liter bottle at 25 yards I'll be happy.

I found a picture of Safarikid's 600 and dropped it in for comparison. With that stock the 18 inch barrel looks pretty long. Seems like his length of pull is kind of short also.

If weight is your concern then you're right, go as short as you deem right. I prefer the swing and balance of the longer barrel but you have to be happy with what's in your hands. It will be tougher to hit the upper range of velocities with the shorter barrels but no one can argue that 900grain, .620 diameter bullet at 1,800-2,000 fps won't be enough.

If the second of the two rifles pictured is supposed to be SAFARIKID's 600 OK, that's not the one to which I was referring which had a laminate stock, fluted barrel and integral brake. A real beauty.

Good luck

56Hawk,

Glad you finally found your way over here. Way different crowd than THR. Good luck on your build.

Hizzie

56 Hawk-Congrats, your gun will probably come in around the 150th .600 overkill built.A few pieces of advice. I built the first .600 ok on a CZ 550 action and unless your gunsmith is real experienced making cartridges like this feed, expect problems. AHR developed a single stack mag box that really corrected the issues many had with the CZ 550 feeding. You will also need a correct reamer or separate throater to allow for solids. The gun was designed to deliver 2400fps with a 900 gr bullet. It will only do that with a 26 inch barrel. The standard load is 165 grs of IMR 7828 under a 900 gr bullet for 2150 fps. With a 18 inch barrel expect 1950 which was the old .600NE tropical load. Make sure you get a stock that fits you and doesn't drop too much. You want the recoil to come straight back. I also strongly advise you to add a good muzzle brake as 200 ft-lbs of recoil can hurt big time. I make 750 gr bullets for this caliber and pm me if I can help further.-Rob

Think I finally got the picture of Safarikid's rifle. I'm really liking the look of the 18 inch barrel.

You won't get quite the velocity out of an 18" tube, but there is plenty of energy to spare on any game. The bottom one is built by Bijou creek and had that awful dreaded muzzle brake that some hate so much.When I shoot the bottom one with the short barrel, I like having the muzzle brake on it. But certainly to each his own.

Welcome aboard the 600 club Hawk. You'll love this round. Truly nothing like it. Mine has a 20" barrel. I won't go shorter as the muzzle blast hunting is stout. You can go with a thinner walled longer barrel to keep weight down as well. An 18 w/o a brake will really clear your sinuses :-)

600 Overkill, your screen name is going to make this post very confusing.

Anyway, that's a nice looking rifle you have there. Just wondering though why yours and most of the other 600 Overkills look like they have really short for-ends. Yours is actually longer than most. Is this an optical illusion, or is there a design reason for it?

56hawk,
I don't believe there is any technical advantage and that the barrel to forend length ratio is determined by aesthetics. That is subjective and I prefer longer barrel/forend ratio whereas you seem to prefer shorter. It's all good and your gun should be built to your liking.

Besides, you can always screw in a new barrel and replace the stock if you want a change. Hope the 600 can handle oranges and grapefruits!

Good luck with the build.

When I built mine, I patterned it after Safari Kid's which is this rifle on AHR's home page. I, like Tom, prefer shorter, fast handling & light weight hunting rifles. If you plan on doing more shooting with it than hunting, I suggest a longer barrel & heavier weight to soak up a little more oomph.

Tom usually builds his rifles with a short LOP to accommodate heavy hunting clothing he uses in Alaska, then uses a slip-on pad/extension in warmer weather. I asked him about that on a couple rifles he showed me.

No offense intended, but these guns look almost cartoonish. When you compare the asthetics of these to the asthetics of a slim, trim British style express rifle, even the large caliber express rifles, they just look odd and misproportioned to me. Same goes for my A-Square Hannibal in .500 A-Square. Again, my comments are limited to asthetics, I am sure that performance wise they are spectacular.

quote:

Originally posted by MJines:
No offense intended, but these guns look almost cartoonish. When you compare the asthetics of these to the asthetics of a slim, trim British style express rifle, even the large caliber express rifles, they just look odd and misproportioned to me.

Can't say I disagree, and if I had the money I'd be getting a Holland & Holland in 600 Nitro Express right now.

I also think a thinner barrel would look better, does anyone know how thin you can safely go? Krieger Barrels recommends a minimum of .875 for both the 600 and 700 Nitro Express. That's quite a difference in wall thickness.

Holland and Hollands are great but who has 185,000 for one. A 600 overkill is about 4000-8000 depending on how fancy it is.

Your dealing with a cartridge that was designed for 65 KPSI. The .600NE was designed for what 40Kpsi? Years ago when I first designed this gun I did the calculations and determined a minimum muzzle diameter .920 to comfortably deal with the level of muzzle pressure produced. If its threaded for a muzzel brake, I'd go 1".
Yes a really nice .600 Ok with a great stock and all the right parts typically costs 4-8K depending of course on who does it.
I think I had <1K in my first one, but I did all the machining and stock work.-Rob

Great to hear from you Rob. I'm surprised that the muzzle diameter would need to be that thick. Especially considering that the chamber is only 1.100 to 1.250 and pressure levels drop pretty quick.

I'll take your word for it though since I'm sure you know way more than I do.

My original plan was to get a Heavy Palma contour barrel for Pac-Nor which has a .925 muzzle diameter. My gunsmith thinks it will be faster to get a barrel blank and contour it ourselves.

I was drawing some ideas up in CAD, but it sounds like the Heavy Palma contour will be about as light as we can go anyway.

By the way, this is more or less a no frills build that I'm hoping to keep under $2,000.

Personally, I'd have Pac-nor contour the barrel blank for you and then button rifle it. You might ask them if they still have the original 3 groove rifling button. The original barrels were made that way to reduce bullet resistance and lower pressures. Later they changes to a multi groove design I'm told, but they may still have the button.-Rob

56hawk:

Here's a couple of pictures of my AHR built .600 OK Rifle. I had Wayne build it with recoil reduction in mind. It has a 24" barrel and weighs a fairly hefty 13.5 lbs. I have not shot it yet minus the muzzle brake....but then, I'm not a big fan of giant recoil.

what is the recoil like with the muzzle brake? i'm going to have one built with a 26'' barrel and will probably get it with a muzzle brake also.

quote:

Originally posted by CHIPB:
56hawk:

Here's a couple of pictures of my AHR built .600 OK Rifle. I had Wayne build it with recoil reduction in mind. It has a 24" barrel and weighs a fairly hefty 13.5 lbs. I have not shot it yet minus the muzzle brake....but then, I'm not a big fan of giant recoil.

Thanks, that looks like a really nice rifle. Recoil must be pretty tame in a 13.5 lb rifle with a brake. I've decided to go with the 18" barrel on mine. Found some pictures of rifles with short barrels and really like the look of the 18":

416-458-50 SS-50 B&M Series Cartridges/Rifles

quote:

what is the recoil like with the muzzle brake? i'm going to have one built with a 26'' barrel and will probably get it with a muzzle brake also.

Pez: I haven't shot a wide range of big bore rifles, but I can tell you that the recoil on my 13.5# .600 OK with the brake installed is far greater than a 9# .375 H&H. I also own a 13 lb. 2 oz. .505 Gibbs that has no break. I would say that the recoil of these 2 rifles is comparable.

I've enclosed a couple of pictures taken at the range showing me firing the .600 OK. Remarkably, my friend shot this picture just as I pulled the trigger. If you look carefully, you can see 2 things here:

1. The gases exiting the brake, and
2. The hood over the front sight flying off during recoil.

Note: no detached retinas, dislocated shoulders, and I haven't been knocked on my but.

The second picture is of me examinng the muzzle of the rifle and wondering what the metallic noise was when the hood hit the floor .

Just for quick reference some numbers to ponder:

(second number = with gas after effect)
7lb 30-06: 150grains @ 3050fps = 15(25) ft-lbs recoil

9lb 375 H&H: 300grains @ 2700fps = 29(48)

9lb 460 Weatherby Magnum: 500grains @ 2600fps = 70(120)

11lb 460 Weatherby Magnum: 500grains @ 2600fps = 60(98)

13.5lb 600 Overkill: 900grains @ 2000fps = 90(144)

13.5lb 600 Overkill: 900grains @ 2400fps = 135(204)

yes i do see those 2 things in the pic! that is an amazing pic! thanks for the info. very nice looking rifle you have also.

quote:

Originally posted by Pez:
what is the recoil like with the muzzle brake? i'm going to have one built with a 26'' barrel and will probably get it with a muzzle brake also.

I always suggest getting a removable brake along with an end-cap. You can play around with the brake on and as you become more comfortable, take it off put the end-cap on to protect the threads and go hunting.

Though I'm sure you know this already, if doing the latter, make certain that POI doesnt change when brake is taken off.

Good luck and have fun. 620 calibers are great!

quote:

Originally posted by CCMDoc:

quote:

Originally posted by Pez:
what is the recoil like with the muzzle brake? i'm going to have one built with a 26'' barrel and will probably get it with a muzzle brake also.

I always suggest getting a removable brake along with an end-cap. You can play around with the brake on and as you become more comfortable, take it off put the end-cap on to protect the threads and go hunting.

Though I'm sure you know this already, if doing the latter, make certain that POI doesnt change when brake is taken off.

Good luck and have fun. 620 calibers are great!

yeah, that is exactly what i'm plaaning on and wouldn't have it any other way. i have a .30-378 Weatherby Mk V with a removable muzzle brake and i'm very glad it's made that way. i wish my Remington model 700 in 375 RUM had a removable muzzle brake and i just may get it rebuilt to have one. oh yeah, and i the 620 calibers are absolutely amazing.

The receiver came in. Only problem is they sent one with a 416 Rigby boltface instead of the 505 Gibbs. Going to call CZ on Monday to find out why. Might just have to open it up on the lathe.

Was also thinking about doing some customizing on the receiver. I don't plan on ever mounting a scope on this rifle, and don't really like the way the built in mounts look. Has anyone seen one where the mounts were machined off?

I'm thinking about rounding off the front and cutting down the rear to the point that it completely removes the funny notch (see lower picture).

Any thoughts?

Barrel showed up, and I'm not too happy with Pac-Nor. It was suppose to come threaded for the receiver and already chambered. Also suppose to have three groove rifling and it has nine. Now I wonder what twist rate they gave it. Oh well, at least they put the right profile on it (Heavy Palma). Getting closer, hopefully I'll get to shoot it one of these days.

re the hood ...
i believe, but i could be wrong, that the rifle is retreating from the hood, rather than flying off... not being nitpicky, i don't think.. but i got into a pretty nasty discussion regarding the direction of scope slipage from someone that SHOULD have known better.... and had to prove it beyond the shadow of a doubt

jeffeosso: you are undoubtedly correct. I just wish I knew how to better secure the hood, because this happens every time I shoot the gun. The only thing that secures it is an allen wrench screw which fits into a notch in the hood as well as the tensil strength of the hood itself which fits into a groove along the front sight. Is it time for a new front sight?

CHIPB,

Are you still having the same problem with that flying hood...? Have you spoken to Wayne about it...?

56hawk,

Just in case you want to avoid dealing with CZ and Pac-Nor, Idaho Sharpshooter is selling the .600OK he commissioned from Wayne at AHR.

It's new, unfired and is still at AHR.

Check the Classifieds for his ad.

George

quote:

Originally posted by GeorgeS:
Idaho Sharpshooter is selling the .600OK he commissioned from Wayne at AHR.

I saw that, but $6,000 is way more than I want to spend right now. Especially since a front sight and a stock is all I have left to get.

WHITE HUNTER BLACK HEART:I haven't yet spoken to Wayne, but I think I'll be seeing him in Las Vegas next week for SCI....so I'll probably cover it then.

quote:

Originally posted by CHIPB:

quote:

what is the recoil like with the muzzle brake? i'm going to have one built with a 26'' barrel and will probably get it with a muzzle brake also.

Pez: I haven't shot a wide range of big bore rifles, but I can tell you that the recoil on my 13.5# .600 OK with the brake installed is far greater than a 9# .375 H&H. I also own a 13 lb. 2 oz. .505 Gibbs that has no break. I would say that the recoil of these 2 rifles is comparable.

I've enclosed a couple of pictures taken at the range showing me firing the .600 OK. Remarkably, my friend shot this picture just as I pulled the trigger. If you look carefully, you can see 2 things here:

1. The gases exiting the brake, and
2. The hood over the front sight flying off during recoil.

Note: no detached retinas, dislocated shoulders, and I haven't been knocked on my but.

The second picture is of me examinng the muzzle of the rifle and wondering what the metallic noise was when the hood hit the floor .

I have to say that nothing about shooting that gun looks fun.

I'm just not man enough...