I've just recently joined the AR forum, but have been visiting as a guest for some time and have developed something of an interest in building a 600 Overkill rifle. Since several of you have rifles in that caliber, I would like to ask your thoughts on building one on a left-handed action.

I'm aware of the LH Granite Mountain action, but, unfortunately, the $2,500 cost of the action, combined with the other likely costs of the rifle, makes that option economically unfeasible. I don't believe that the Montana Rifleman PH action is or will be available in LH in the near future.

Would a Weatherby action work? I have a .378 rifle, and the magazine is long enough to accomodate the .600 cartridge. Weatherby makes a drop floorplate that adds a third round to the magazine (in .378), which might be needed for the larger diameter of the .600 case. I'm not concerned about the push-feed action because this rifle would be used more for fun than for anything serious. I would guess that the bolt face and extractor need to be enlarged also.

Also, any recommendations for barrel dimensions?

If you don't believe that the Weatherby will work, any suggestions?

I would greatly appreciate your thoughts.

Howdy and Welcome.
Rob invented the beast, and may have the info...

the weatherby WILL hold the 550 magnum, 550 express, 500 mbogo/wells/a2, 500 AR, or a 470 Mbogo
jeffe

What about a Montana 1999? I know they can get a Lott in one.

LH Magnum= Welcome to the .600OK brotherhood. Personally while being left handed myself, I prefer a right hand bolt. Long ago I trained myself to use a rt hand bolt and its payed off big time. That way the bolt handle cant hit you on recoil. The .600 OK at full 2400fps is a monster to handle and I;ve seen the bolt handle rip peoples hands severely. Nevertheless, I see no reason a WBY LH action wont work for a .600Ok. The barrel dimensions vary all over the place but you basically want a 5 inch straight cylinder over the chamber and a taper to NTL .890 at the muzzel. You will lose 25fps/inch from 26 inches. I also advise a good muzzel brake be part of your design. The single stack feature of the wby is definately a plus and you will want to retain it. A bit of serious machining will be required( .600 Ok case is much larger in diameter than a .460Wby case. as well as a custom U shaped follower. Yes, the bolt face will need to be opened up and re heat treated. Pac Nor and or AHR will have a reamer for the .600Ok. Otherwise you will need to talk to me. I too dont really care about the whole push feed vs CRF issue. Biggest issue is the WBy stock which will punish you big time in something like this assuming it survives two shots. I would definately advise you to change the stock. Remember,everything has been worked out for the CZ550 and GMA actions you might consider selling the WBY and putting the money into a tried and true system.Irregardless, Its the most bang for the buck you can imagine. You really should talk to AHR as they offer a reliable, on time build that flat out works. For the time, money and anguish involved with a specialized weapon like this, why tread new ground? Either way, you will have a ball. PM me if you want morec spoecifics.-Rob

Rob,

Thanks for the quick response. You've given me a lot to consider, especially the bolt handle issue. I can certainly shoot a right-hand bolt: I grew up doing that, but, if shot from the left side, it requires that the rifle come down from the shoulder, which slows the second shot. Of course, there may not be any such thing as quick second shot with a .600 OK! Thinking about it, I just can't envision how the bolt handle hits your hand when the shot goes off. Is that from torque? Does that happen even with a muzzle brake?

Also, I had not thought of the need for the U-shaped follower. (Something like the original .500 Jeffrey/Schuler ?) I was thinking that the flat follower of the Weatherby might work.

Regarding the stock and brake: I agree and would definitely restock it and install a brake. If nothing else, the forearm on the .378 is just too thin for a much larger barrel. I put a brake on the .378 about 17 years ago and have really enjoyed it. (The velocity with which an 8.5 pound rifle with no brake recoils when shooting 300 grains at 3,000 fps is amazing! Especially from the bench or prone.)

Given the amount of re-work necessary on the WBY, I may just try something that fits more easily (a .500 or .550), or try the right-hand CZ .600, or save my pennies for the additional $2,500 for the GMA action. Like I said at the outset, you've given me lots to consider. Thanks again.

Stephen

LH Magnum- A right handed shooter has his wrist and hand on the stock behind the rt hand bolt. Depending on how strong their grip is, on recoil, their hand can come foreward smacking their trigger finger into the triggerguard and sometimes their hand into a swept back bolt. Nasty wounds can result. A .600Ok without a break can be a handfull! Same problem for us lefties with a LH bolt. No problem for a lefty with a right hand bolt. Finally we have an advantage. Yes Schuler knew what he was doing with that U shaped follower. No a flat follower wont work. Let me know if you need any info or want to discuss your ideas further. Glad to help.-Rob