I have a 600 Overkill being built by AHR. Should be ready in December.
Talking with Wayne on the phone he suggested using H4350 as the go to powder for 900 gr bullets.
With powder being hard to find these days, I backordered a few pounds of it from Grafs. Hopefully I'll have it by Dec.
Are there any other powders you guys with 600 OK would suggest I should backorder as well?

Well since I invented the cartridge, I'd suggest you start with 163-165 gr of IMR 7828 and a 900 gr woodleigh. You'll need a 24 inch drop tube to get the powder into the case. with a 26 inch barrel you'll see 2150 fps. Thats a nice introductory load. Most folks never feel they need more in fact! H414 can deliver max horsepower in the .600 OK.-Rob

Thank you for the info. I sent you a PM regarding the 414.
Bob

Couple of things:

Wayne and AHR - fantastic to work with and a great guy. I was so pleased with the 600OK built for me, I had them build a 585AHR for my dad. Both were used for a Cape Buffalo and PG hunt in Zimbabwe and performed flawlessly. OH, and they made really big holes.

Loading for the 600 - easy but be careful about collapsing the case neck. My 9 year old daughter never did so when helping me load the 600 but I have.

Powders - I have used Reloder 19, 22, 25, Vhitavhouri N560 and N550, WW760 and 748, H414, H4350 and IMR7828 with a wide variety of bullets. All work well, some are "dirtier" than others and you can achieve the 2,100 - 2,200fps with just about anything - and it is plenty of horsepower. I bring this up simply because of the powder availability issues but fully agree with RGB about what works best.

Good luck - you will love it.

CCMDoc, thank you for the reply. Given the powder availability issue, it's good to know that I can use a variety of powders in this 600 OK. I found some H414 available. Cabela's has it in stock if anyone is looking for it.

I agree about Wayne at AHR. He has been very helpful and is very easy to reach. He took about an hour out of his time to answer all my questions regarding this rifle. I look forward to seeing and shooting the gun when he is done building it.

Bob

Varget works good as well if the powders Rob and Paul recommended are not available. You will be most impressed with Waynes work and the bad ass cartridge Rob designed!! Good Luck!

SA85 - PM was sent with info requested.

Have fun and good luck!

CCMDoc, I just got your PM and I greatly appreciate you sharing the load data with me.

Bob

I'm confused that various posters would recommend both VARGET and IMR7828 for the same cartridge and bullet, due to the greatly different burning rates.

I don't know anything about the 600-OK but...if one had a 300 Weatherby, 7828 would be about right but VARGET would never give you anywhere near maximum velocity. With a .458 Winchester, VARGET would be worthwhile but a decent 7828 load would not fit in the case. So it goes.

Indy- welcome to the world of high capacity straight walled cases. Both Varget and IMR 7828 work as do many other powders. Get a copy of quickload, put in the case info and see for yourself. This cartridge is actually very versatile and easy to reload for. You can go from mild to rips the gun out of your hands with just a change of powder.
Sa85- Dont forget the 750 gr bullets in the .600OK. They really move!-Rob

Rob,

I missed some of the early posts on the 600-OK. What is it? A rimless 600 Nitro Express intended for bolt actions? And how do you get rifles for it?

quote:

Originally posted by Indy:
Rob,

I missed some of the early posts on the 600-OK. What is it? A rimless 600 Nitro Express intended for bolt actions? And how do you get rifles for it?

Im not Rob, but one of the people who have benefitted from his invention.

Basically, due to his dissatisfaction with the 585Nyati, Rob designed and developed the 600 Overkill (and slightly longer OK-2 and OK-3).

Basically a belted, rimless 600 NE intended to reach much higher pressures in bolt-action rifles, it can (and has in Rob's hands as well as my own) reach and exceed 2,400fps with a 900 grain bullet and 2,750fps with 750grainers.

It has been built on a variety of magnum actions but most commonly on CZ and GMA actions.

It has been used by quite a number of us to take all sorts of game from groundhogs to Michigan Boar to Cape Buffalo with fantastic reults.

Easy to load, easy to shoot and fun to have, rifles have been home-brewed though most built by American Hunting Rifles. Bijou Creek has recently joined the ranks of buliders.

Rob and fritz454 as well as jeffeosso can probably provide much more info and SAFARIKID asquite a bit of field experience with it on African Game.

Stay well,
Paul

Those 750gr bullets would really work well on my hunting spot in northern MI. I hunt on an area that was recently logged and can see about 500 yards from my stand. The 750gr bullets sound like they would be a good deer slayer from my spot. Could you guys let me know of a source for the 750gr? I looked on midway and just saw 900 gr available.

Bob

quote:

Originally posted by sa85:
Those 750gr bullets would really work well on my hunting spot in northern MI. I hunt on an area that was recently logged and can see about 500 yards from my stand. The 750gr bullets sound like they would be a good deer slayer from my spot. Could you guys let me know of a source for the 750gr? I looked on midway and just saw 900 gr available.

Bob

Hi Bob,

That wacky inventor - Rob Gun Builder - povided me with a supply that, alas, is long gone. I'll have to hit him up for more. Be aware, though, that once launched, tehy keep going and going and going and it seels nothing stops them I think mine are still flying!

I think the only place you can get them is Rob.

Stay well,
Paul

P.S. Check for a PM I am about to send regarding some other projectiles.