Sandman S POI Shift This Time...

opus56

Online Training Member
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Minuteman
Apr 24, 2018
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18
Utah
www.sagerssohne.com
Hey everyone,

I recently got my Sandman S and am using it on a couple of different rifles using their keymount brake on both rifles. On my 224 Grendel (AR15 platform) the POI shift with suppressor is what I would say is very normal, a .3 mil shift. But on my AR10 (.308), the shift is 8 mils right and 3 mils up. With that much change I figured there must be something else going on, like maybe scope or scope mount...but the optics are all good.

Anyhow, I put the Area 419 brake back on which I've had on the rifle since I built it, rezeroed, and the rifle shot as expected. Then I put the keymount brake on again, rezeroed, and the rifle shot as expected. But as soon as I put on the Sandman, the POI shift is huge and it's not consistent either. It's not like it prints 1/2 MOA groups at 8 mils right and 3 mils up. It won't shoot even a 3 MOA group. No evidence of a baffle strike. Everything looks normal.

The AR10 has a Lothar Walther KA profile 20" barrel and it's been a consistent 1/2 MOA shooter ever since I assembled the rifle. Could I have a bad keymount brake?

Thanks in advance for your help.
 

Pvt.Donut

Private
Belligerents
Apr 4, 2017
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How is your Keymount mounted to the 308? You're using the supplied shims right and not a crush washer or something?
 

opus56

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Minuteman
Apr 24, 2018
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Utah
www.sagerssohne.com
How is your Keymount mounted to the 308? You're using the supplied shims right and not a crush washer or something?
Yes, I used the Dead Air shim kit. I also contacted Dead Air and they are sending me another keymount brake to try. Along with that I'm going to use a section of 19/64" drill rod to see how the suppressor lines up w/ the bore. If I don't get the results I'm looking for, I'll pull the barrel and have the thread concentricity checked.
 

opus56

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Minuteman
Apr 24, 2018
22
25
18
Utah
www.sagerssohne.com
Got the 19/64" rod today and the suppressor is definitely not concentric to the bore. Once I get the new keymount brake, I'll take a look again. I'm hoping it's the mount and not the barrel...but I guess we'll see.7043538