adjustments relating to a muzzle brake?

[Mtnmn09]

I have been working on a heavy barrel .308 for a couple years now, slowly increasing my distance and confidence in adjustments. Today I installed a muzzle brake, and returned to the same location I often shoot only to find my adjustments were way off. I was shooting out to about 700 yards and my calculator was usually pretty close. However, today my calculator called for 7.2 MOA at 385 and I found myself about 3 MOA over the target. At 500 I was pretty close at 9 MOA until today where 5 MOA was within 4" of my target. I am curious if I have changed something too drastic and need to remove the brake and go back to what I was doing ok with? Any advise or help is appreciated.

[jeffro]

Adding a brake can make a difference in a load as it changes barrel harmonics. You should re zero and check groups any time you change something. Its like hanging a weight at the end of the barrel. Also check for baffle strikes if your groups are bad or worse than before.

[lancetkenyon]

What kind of muzzle brake?

Clamp on or thread on?

Make/model?

Bore dimensions?

Who did the install?

[jeffro]

With the size of that thing, I guarantee the harmonics have change drastically. New load development may also be needed. Bullet trajectory, and the node will have changed.

[Mtnmn09]

Well at the moment I am not sure if I should stick it out with what I have built or just go ahead and purchase a smaller brake. If the rifle groups great, I will be happy and put more time into my own chart. Unless you think the large brake will cause any damage or issues down the road?

[AxisWorks LLC]

+1 on harmonics. If your going to stick with that brake your back to starting over with load development. Personally I'd go with a Vias, muscle or mini bastard brake.

[jeffro]

You can use that brake, just start your load del over again and see what your rifle likes now. Usually, if it shot good before, it will still shoot with some tuning. Is that off a 50cal?

[jeffro]

You cant hurt your rifle with that brake .

[lancetkenyon]

Holy huge brakes Batman! The weight alone would help reduce recoil, let alone the porting.

As others have stated, that weight on the end of the barrel should not hurt the rifle, but will definitely change the barrel harmonics. Do a quick ladder test with loads similar to what you have been shooting to see where the accuracy node shifted to. I bet within a grain of powder +/- you will be close.

[muledeerarea33?]

Why brake a .308?

[Mtnmn09]

The design is based off of some 50 brakes, but it was built to be put on this rifle. I have larger calibers, but I wanted this rifle (since already heavy) to be like shooting a small caliber, yet able to reach out and touch something. I appreciate the input, when I get the chance again I will take it out and test it.

[lancetkenyon]

My son-in-law has a .308 that his father had built in Washington, and it kicks like a freaking mule! It is seriously worse than my .300RUM was without a brake. Not an exaggeration.

 

Super light, like 5#, and a very hard rubber butt pad. I actually checked the bore dimensions to see if it was a .7mm or .264 bore that was mismarked with a .308 stamp on the barrel. I have shot some big guns, up to .30-378 Weatherby and .338 Mags with no brakes, and I swear they were not this bad.

 

My son-in-law couldn't do more than 5 rounds, and I got to 6 before I told him load development was suspended on the gun. It has now been sitting for 2 years in a safe. Beautiful gun, and would make a great mountain gun if you put a brake on it. But I ain't shooting it any more.

[maximus]

i have a savage model 12 that i changed the stock, i put a choate varmint stock and have no recoil at all, no need for musclebreak.

[MULEPACKHUNTER]

Barrel whip for sure has changed. Ladder test needed?