Added a brake and lost all accuracy- WTH?

[Jesse Jaymes]

Had a very notable gunsmith prune a Tikka T3X back to 19" and thread/time a Mini Beast 3 port brake. I didn't dick with the rifle too much before I had the work completed. A few groups and there were no accuracy issues. Thrown together handled was MOAish.

Got the rifle back and have begun to futz with it. Was really chasing my tail for a bit. Pull the brake off and put the threaded cap on. Shot on paper and not steel. Was able to put 5 rounds - some of them .090" off the lands and the others .020" off as I was testing seating depth and max Tikka magazine COAL.....into 5/8 of an inch.

Put the brake back on and I don't even have all 3 rounds on paper. To that point, the impact is 5 1/4" lower with the brake added. It's just a dinky little 3 port. Doesn't weigh all that much.

I realize the obvious answer is to shoot it with the threaded cap, schit can the Mini Beast...and rock on.

I am generally pretty recoil tolerant. But a T3X with a 22oz Leupold in Sportsmatch, but 5" of missing barrel weight....gives me an F'ing headache after 6 rounds prone. I didn't chrono any data prior to pruning the barrel, but with 185 Bergers...it's a Dog. So I am standing on it trying to crack 2700.

Gunsmith is one of the most respected and competent 'Smiths there is. Obviously shoots great with the threaded cap.

Try a different brake? The barrel being shortened to 19" I would expect it to be even more stiff. I am rather floored at over 5" of POI shift at only 100 yards.

Thoughts?

 

[SDHNTR]

The chop and the brake changed the barrel’s harmonics. Of course it’s going to change poi. It might even change the load preference. Doesn’t surprise me. Every time I’ve chopped and/or threaded and braked a barrel I’ve expected to start over.

 

[WKR]

Thoughts are, put a can on and work up a whole new load, and that gun is going to suck to shoot unless you put a suppressor on the end of it. A muzzle brake is just going to amplify that suck.
The concussion from short barreled magnum cartridges is unbearable after more than a couple rounds.

 

[JohnB]

You are surprised that you had a drastically different point of impact after you lost 5 inches of barrel and around 100-150 fps of velocity??

What did you think was going to happen?

From my read his upper group was post barrel chop with the threaded cap and the lower two bullets were with the brake attached.

 

[Jbehredt]

Long shot but is the brake bored cleanly?

 

[WKR]

From my read his upper group was post barrel chop with the threaded cap and the lower two bullets were with the brake attached.

I think you are right ill edit my post

 

[waspocrew]

How does the brake look? Any bullet strikes? I wouldn’t expect that much POI shift with a brake.

 

[Acharenio]

magnum's are best with longer barrels, i think 19" is too short for a 300wm.

 

[Jason Snyder]

I would contact the brake company. Any signs of contact inside the brake? Does it seem to thread true onto the barrel ?

Edit looks like waspocrew was typing the same thing I was thinking.

 

[Jesse Jaymes]

To clarify...those groups are fired same day. Brake on and Brake off. It's not a pre and post pruning group test.

I thought similar to a baffle strike inside a can....I don't SEE any internal issues or strikes on the brake.

 

[Jesse Jaymes]

Brake threads on very cleanly and straight...by my eye.

 

[Jesse Jaymes]

Also kinda funny the thoughts on barrel length. There are more than a few handfuls of the more respected RS posters who fully endorse barrel chops on "Magnums". Many would have gone 17".

I don't have a 1/2- .308 can. Was never really where I wanted to end up with this rifle. Wanted a short, handy, rut-rattling rifle and mountain rifle. Never intended to add 11 ounces back to the build in the form of a Can, nor put the barrel length back on. Wanted a higher HP whacker than a short Creed. Have many other rigs to fill many other uses. This was to be a niche rifle. Still is.

So with the same 19" barrel...one group WITH the brake and one WITHOUT I am kinda floored with over 5" of POI deviation.

I can add a 12 ounce suppressor to other rifles barrels and only deviate 2" or so at 100.

 

[waspocrew]

magnum's are best with longer barrels, i think 19" is too short for a 300wm.

I don’t think that’s necessarily true… also, I don’t think his barrel length is the issue here. Rifle is plenty accurate without the brake on.

OP - Have you spoke with the gunsmith?

 

[Axlrod]

If it were mine, the first things I would have done is:
Check brake to make sure it is tight
look for bullet strikes
call the gunsmith

 

[WeiserBucks]

Have you attempted to zero the scope and shoot any more with the brake? This might be a big fat nothing burger.

 

[Jesse Jaymes]

I guess you lost me??? Easy to argue I'm a 1/2 MOA hot....but this isn't the first group or sample set I've struggled with Brake vs No Brake.

The brake is significantly less accurate....and POI is significantly different each attempt. It's repeatably schittty

 

[WeiserBucks]

Try a different brake, they're not big $$$

 

[Jesse Jaymes]

I've not contacted the Smith. He's a solid guy. Decades of service.

Was trying to get some insight prior.

I liken that to calling the Breeder if your dog bites someone....

 

[Jesse Jaymes]

Probably the direction I will head. Even a cheap radial brake would take some of the bite out. Easy to test I would think. Just don't have any 30 cal brakes handy on 1/2-28

 

[Dioni A]

Good odds that there's nothing wrong with any of it. I have seen guns that shoot great open up dramatically with a break. Change the brake and it shoots great again. Same break on another gun shoots great.