BayouBob

The outside diameters of the Cooley muzzle brakes are listed in the chart on the JP Rifles web site. With a Cooley brake on my 308 the muzzle just sat still when I fired. Be prpared for LOUD though. If you shoot at a range where there are other shooters on either side of you, particulary a covered range you will Not be popular.

Do you send money to Gun Owners of America or the Second Amendment Foundation or do you just sit on the sidelines and gripe about the NRA and let others carry the load?

You can figure on your powder costing you around 20 cents per shot. Inexpensive bullets are around 30 cents each and premium bullets are close to 1 dollar each. Primers run around a nickel each. If you have or can scrounge brass it won't be a cost factor. (Although it does have a finite reloading life) If you buy new brass it will run you around 50 cents per for standard quality brass. So, you are looking at anywhere from $10 to $35 per box for the cost of your components. You will amortize your basic $3-400 reloading set-up in your first 30 boxes of ammo. Of course, as my Dad had to go and point out to my wife, you won't save money; you'll just get to shoot more!

When the OP goes to buy reloading components he will find them just as scarce as loaded ammo. Powder, primer and popular bullets are almost impossible to find.

Some folks have gotten outstanding accuracy with their MK 3's. Mine shoots right at an inch with Federal Gold Medal Match 168 gr. Sierra Matchkings. It took trying a couple of dozen loads before I finally found a hunting load that stays close to an inch. I settled on 165 gr. Sierra Gameking hollow points as the most accurate bullets out of my rifle.

If you look around I think you can find a front sight that is designed to sit on a low profile gas block and be in line with a standard height rear sight.

I agree with 98Z and the other guys about the gas block. Something isn't right about it. I put a PRI adjustable gas block on my CMMG 308 and cured all the problems the factory couldn't figure out. If you do replace the block go with an adjustable model; it only costs a few dollars more and you can tailor it to your rifle.

Are you getting any stovepipes on failure to eject? How did you establish the point to set the gas block? If it is too far back you may be banging the rear of your gas tube on the gas key. Check and see if it is getting bunged up. If it is too far forward you may not be getting enough gas into the tube or the gas may be getting around the edge of the gas key and not giving you enough pressure to consistently cycle.

They have a saying about Rossi, which I have unfortunately found to be true; "Their customers are their quality control department." I'm beginning to think the same can be said of CMMG.

They must not be big on tightening things at CMMG. In addition to the gassing problems, mine came with all the hand guard screws loose enough that the hand guard wobbled back and forth over 1/4 inch.

And the "Chosen One" shoots skeet all the time too. As if that has anything to do with the current argument.

Let us know how it works out. It will be interesting to see how many times he has too send it back to CMMG before they figure out it has a loose barrel.

Although the megalomaniac in the white house doesn't seem to care about a faded old piece of paper, I don't remember anything in the Constitution giving the president the authority to make law. It's a shame that when he does the joint chiefs don't order an airborne division to move into the white house and arrest him.

I tried the JP Cooley style muzzle brake on my CMMG. It made the recoil just go away but it doesn't reduce flash at all. I ended up getting a grind to fit Limbsaver pad and shaping it to fit the A-2 buttstock. You need a couple of spacers under the lower end and you may have to order a longer screw to attach it to the buffer tube but it ended up looking good and does a great job of reducing what little recoil a 308 has. Since I will do some night time hog hunting with my 308 I wanted flash suppression so I put the stainless bird cage flash hider from Armalite on the rifle.

Figured it out. The buffer spring appears to be a standard DPMS 308 heavy spring with 39 coils. The bolt catch was evidently a plain AR-15 catch. The flat part of the catch that sits down in slot of the receiver was just a little thinner than the slot was wide. That allowed it to lean a little bit toward the front of the receiver when the bolt pushed on it with the heavy spring causing the catch to bind and not want to move out of contact with the bolt and causing the bolt to wear a groove in the face of the catch. I replaced the catch with a DPMS purpose built AR 308 bolt catch. The DPMS catch is just a tiny bit thicker than the one that came on the rifle so there is no slop in its fit in the slot. Instantly, without even polishing the face of the catch, the pressure on the button to release the bolt catch dropped by 2/3. It takes just a little more effort to push the bolt release than on an AR-15. I can still tell there is a strong spring pushing against it but it is smooth. I have passed my observation on to CMMG since they didn't seem interested in addressing the issue.

Blazer, There are some rail height picatinny gas blocks out there. Depending on the diameter of your barrel at the gas port you can probably find one that will put your rails on the same plane. You just have to make sure your handguard isn't so long that it goes over the gas block. Another alternative is to get a longer handguard that has a receiver height rail its full length if you want to put iron sights on.

Thanks Robo, I was just playing around with the Cooley comp. I like to try a little of everything on my rifles. I end up spending as much as the rifle costs on various accessories most of the time. Since the 308 has very little recoil anyway and after grinding a Sims recoil pad to extend the length of pull on the A2 stock I am happy with just a flash hider. If I wasn't planning on shooting at some hogs at night I wouldn't even use that; I'd just put a thread protector on it.

Thanks Wash. I tried the JP Cooley comp. It worked wonderfully and looked wicked. I think I could have put an egg between my shoulder and the rifle and not broken it. (The blast pressure was kind of awesome.) Apparently though it affected the harmonics of the barrel because my groups opened up from around an inch to 3 inches. I was accused on the smart ass board of flinching but I don't think that was the issue.

Curiouser and Curiouser. I swapped out the spring from my Sig M400 A2 with the spring in the Mark 3. (The Sig bolt catch release is smooth as glass.) The spring from the Mark 3 in the Sig was a little heavier to release but still smooth. The spring from the Sig in the Mark 3 was a little easier to release but still took quite a bit of pressure, much more than when it was in the Sig. That tells me that at least part of the problem is the contact between the bolt and the catch. I guess the next step is to get a new bolt catch and see if that makes a difference.

Thanks for the tip. I think this looks better than the black flash hider on the stainless barrel.

What is interesting is that CMMG says all their 308's are like that. I may also replace the bolt catch. Does anyone know if the bolt catch is a surface hardened part? If it is not, I could try polishing it to see if that is the problem. It could also be a fault in the bolt.

CMMG seems to think it is no big deal. I have owned 11 other AR's in various calibers (This is my first 308.) and Uncle Sam let me play with M1's, M14's and M16's. I have never seen a bolt catch that was under pressure remotely like this. I am going to put a standard A2 spring in it just to see if it is only the spring that is the cause. The adventures sure do continue with this rifle.

To release mine it takes what feels like 30 or 40 pounds of pressure on the release. It has been that way both when it had the carbine stock and even worse with the A2 stock. I have put high temp bearing grease on it to smooth it but it helps very little. The bolt catch actually has a groove worn in it from the bolt hitting it. I've got around a thousand rounds through it and it still feels like it is trying to tear itself apart. The only solution to the heavy release effort I can think of is a lighter spring.

Have you guys noticed an unusually heavy pressure on your bolt catch?

Am I overlooking something? My CMMG Mark 3 has an A2 stock and buffer assembly. (One of CMMG's fruitless attempts to correct the overgassed issue.) I put an adjustable gas block on the rifle and am now able to regulate the action for my chosen load. The buffer spring CMMG put in the stock must have come off the shock absorber for a 3/4 ton truck. It binds against the bolt catch so hard it takes both hands to push the release. The catch already has a groove worn in it from the pressure of the bolt coming to rest on it. Since I can tailor the amount of gas and therefor the violence of the bolt carrier movement shouldn't I be able to use a lighter power spring to relieve some of the pressure on the bolt catch?