Gunsmithing Accuracy drop off with brake.

[LRJammer]

I recently had a my Win M-70 action squared up and a new Hart barrel installed by my local smith. At the same time, he threaded and timed a Holland QD brake for me. When I began doing my load development, I was getting 0.4-0.6" groups with some loads. With no more than 100 rounds down the tube, the accuracy dropped off significantly (1.5-3.0 MOA) and has even started throwing random flyers about 4-5" to the side. The brake timing now seems to be just a smidge late now as well with the top ports just a bit off center when they were originally perfectly straight.

In a fit of frustration, I took the muzzle brake off and tried the rifle with the last few loaded rounds that I had on hand and it shot better, abeit with a sharp increase in recoil.

Any ideas on what could make the accuracy drop off like this?

 

[Prophet78]

I've been told brakes do affect accuracy. I think you've answered your own question. I would check timing and see if it will improve. I'd throw a fit if I sank a bunch of money in a rig and then it dropped accuracy that much. And I may be in the same boat!

-JD-

 

[Graham]

A properly installed brake does not affect the accuracy of the rifle.

 

[LRJammer]

That was my understanding as well Graham and it demonstrated very good accuracy before I had even had a chance to refine a load for it.

 

[dieselgeek]

I had bad luck w/ an Ops Inc brake, I pulled it off, and the rifle shot very well.

 

[LRJammer]

Ok. Looks like I have a boatload of egg on my face but I started the thread, so I have to come clean.

In looking back at the targets that were shot with the brake off, they still werent showing the kind of accuracy that it had shown it was capable of. My years as a auto tecnician and field engineer have taught me that the most simple explanation is more often than not, the correct one, so I went back to basics and started looking at my scope rings and base. Sure enough, the base screws had loosened up. I got in a hurry when I got everything in and didnt do the job right the first time like I knew I should. Cleaned everything up and have bedded the base. Tomorrow I will clean it up and torque everything up with locktite.

Every now and then I guess I just have to re-learn the hard way I guess.

 

[Rprecision]

Ok. Looks like I have a boatload of egg on my face but I started the thread, so I have to come clean.

In looking back at the targets that were shot with the brake off, they still werent showing the kind of accuracy that it had shown it was capable of. My years as a auto tecnician and field engineer have taught me that the most simple explanation is more often than not, the correct one, so I went back to basics and started looking at my scope rings and base. Sure enough, the base screws had loosened up. I got in a hurry when I got everything in and didnt do the job right the first time like I knew I should. Cleaned everything up and have bedded the base. Tomorrow I will clean it up and torque everything up with locktite.

Every now and then I guess I just have to re-learn the hard way I guess.

I hate finding out the problem was me, That's life..............

 

[LRJammer]

I hate finding out the problem was me, That's life..............

I'm just tickled that it was something easily fixed.

 

[Tristian19]

I'm just tickled that it was something easily fixed.

Ehhhh. Don't be ticked. Consider just being happy it was something as easy as it was with no cost involved and get out there and shoot.

Be safe and enjoy her!

 

[LRJammer]

Ehhhh. Don't be ticked. Consider just being happy it was something as easy as it was with no cost involved and get out there and shoot.

Be safe and enjoy her!

You will notice that I said tickled, not ticked. Vast difference with that one extra letter, and it goes without saying that I am happy about it.

 

[eravelo]

I had bad luck w/ an Ops Inc brake, I pulled it off, and the rifle shot very well.

Allmost a necropost, but here it goes...

Any brake not concentric to the bore, with burrs in the brake bore, which has been overtorqued onto the muzzle, will open your groups.
The 30 cal 12th model Ops Inc brake on my Remington 5R barrel did not affect group size when installed, and shooting with the can shrinks group size, but then this is a factory barrel which can't go below 0.5 MOA in my 1 MOA hands.
My 5.56 cal 12th model brake did not change groups on my Noveske barrel, 0.75 MOA with Hornady 75g steel practice ammo, but I have not shot this much as I am waiting for the Ops Inc 12th model to break out of ATF jail this month. This brake was attached with a crush washer/shim to less than a quarter turn crush.

Wes Grant @ MSTN has written the 5.56 12th Model brake (and the KAC NT-4 adapter) are the only two adapters made with precision, with no affect on acuracy.

Mark @ Accurate Ordnance is also a fan of Ops Inc / Allen Engineering cans but he writes that the brake DOES open up groups, an effect countered by the can.

YMMV