Sako S20 Muzzle Brake

1

I have a relatively new Sako S20 in 6.5 PRC and added the Sako muzzle brake to keep it from jumping around as much. After adding the brake my groupings went from sub-MOA to around 2 MOA. I took the brake off and the groupings went back to normal. I hand tightened it on as I didn’t see any documentation about the torque specs. It was still tight went I took it off.

I am assuming that it was at a torque spec that caused the issue. Any thoughts on this?

BTW, I’m new here and new to bolt rifles and hunting.

2

Unless you’re hercules, or one of his descendants, I highly doubt that you were able to over torque the muzzle brake by hand. Most of the brakes I have put on have specs somewhere between 20 to 30 ft pounds. Obviously can’t say the specific for that particular brake though

Muzzle brakes can lead to worsening accuracy under the following conditions.

  1. Over torquing, constricting the passage for the bullet.

  2. The muzzle brake is loose and Wobbles around even by the fractions of the hair of a head will lead to bad accuracy.

  3. The often overused term, Barrel harmonics. You are adding weight to the end of the barrel which will change its resonance and that can lead to group problems.

  4. Sometimes brakes will actually increase flinching because of the significant amount of blast/ concussion. The rifle doesn’t push back as hard against the shoulder but that concussion can actually make me Flinch more than without a brake

3

do you have another break to put on to test it against?

4

I have a Tikka Roughtech in 300 WSM with a brake. One time at the range my groups started opening up and I found the brake had gotten a little loose. Can’t say this is what happened with this Sako, but that can be a problem.

5

Yeah, it doesn’t take much at all to get things messed up.

6

Thank you all for the responses and ideas. @BEN - I think my son has a different brake that I can try. It’s a good idea.

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7

That’s odd. I haven’t seen a muzzle brake do that unless it’s loose. I just tighten with a wrench to “firm” but don’t follow any torque setting.

8

I was going to suggest contacting Sako, but contact info seems hard to come by. There’s a phone number for Finland ($$$): (+358) 10 830 5200
or you could ask them for a torque range or other advice on their Facebook page and see if they answer: Sako

According to Brownells: absent specific torque requirement from the manufacturer, “it’s essential not to exceed 30 foot-pounds of torque”…so maybe torque it to 25 ft-lbs?
An AI bot told me: “hand tight…with a little extra snugging using a wrench” …which is consistent with Jim’s comment.

if you’re satisfied it’s sufficiently snug on your muzzle but still not grouping well, you might also try some different ammo.

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9

Thank you, all for the great advice.