Suppressors Extreme POI Shift with Saker 762

[adamyq]

I took my 20" OBR to the range today to rezero at 200 with the new brake as well as to check out the POI shift with my Saker installed. I searched through several pages of discussion as well as did some google searches and found nothing, though I am sure some troll will dig up an obscure post, but so be it.

I converted my Saker 726 to use the MAAD ASR mount as I also have a Specwar, so i can interchange the suppressors on all my rifles. I installed the ARS brake on my OBR 762 and headed to the range. I got it all dialed in with tight groups at 200, then installed the suppressor. Shots not even on the paper. Not even in my FOV. I ask the guy next to me to spot, and he said i was hitting just short of the berm. I only had a few rounds left, so i used the reticle to estimate the drop, and concluded it was somewhere between 10 and 15 MOA. After a total of 5 rounds with the suppressor on, I removed it to check the rifle.....still zeroed perfect.

Now I would have understood something like a 2 MOA shift, and maybe even double that if i had some strange harmonic situation going on, but 10+? Something is off. I checked the suppressor and there are no signs of contact (a huge relief). The things I have considered:

1. Threads not aligned? I suppose it is possible, but this isn't some Frankenstein DPMS rifle.....Larue makes good stuff. I do plan to get a ~30 cal rod and check, though a quick check on my MB looked perfect.

2. Random ammo problem? I was using factory FGMM today, no reloads. I did not have my Labradar with me to confirm, but I have been seeing ~2525 ft/s with a StdDev of 10 on those, so low probability.

3. Something odd about the suppressor? I have read many posts about Saker 762s and every one of them showed a POI shift like what i was expecting.

4. Something with the baffle notch clocking? I timed my brake using the shims. I did check the baffle notch alignment, see attached (top of photo parallel to top rail). I don't see how this baffle clocking would translate to a massive drop.

Random other info....I put the same suppressor on my 16' AR to investigate the shift at 100 yards, and got the ~2 MOA shift I expected. I know the suppressor bore being larger translates to more open space and less suppressor effect on bullet (and less suppressive effect), but didnt hurt to confirm.

Thoughts?

 

[HansohnBrothers]

It happens. Some barrel/silencer combinations just don't play well together.

 

[wchartz]

I had something similar happen and just today got the answer. I have a YHM Ti30 installed on my 6.5x47. It has a 1.25 MOA shift when installed and the groups go from about .4 MOA to about . 6 MOA. I bought a DPMS Recon II in 308. It is a 1 MOA rifle with my handloads. I Bought a YHM brake/quick connect, removed the OEM flash hider and installed the YHM brake/adapter on the DPMS according to instructions. My groups opened up to about 2.5 MOA without the can. With the can installed the groups opened up to 8 MOA+. How much plus I can't say since five shots in a row would not land on an 8.5x11 target. I sent my upper, adapter and can to YHM for evaluation. I was sure the center of the can bore was not in line with the rifle bore. I suspected the threads on the adapter and or the rifle were not centered. My diagnosis was right but the reason was wrong. The YHM gunsmith called me and said this was a strange case but he finally figured it out. The threads on the barrel, adapter and can were all within specs. The problem turned out to be the small OD of the barrel and the shims for timing the brake. With a small OD barrel the shims do not have enough bearing surface and crush unevenly against the shoulder of the barrel and cant the adapter ever so slightly, not enough for a bullet strike on the ID of the can but enough to upset the bullet as it left the can. If I recall correctly, I used two .002 shims and either a .005 or a .010 shim. His recommendation was to install a flash hider adapter which does not require shims and then install the can. He said he would swap the adapters at no cost to me. I will follow up this discussion after I get it back and test again.

 

[littlehendrick]

On my remington 700 in 308, my Saker had a 1.6 mil shift, straight down. It was consistent for me. It was a large shift, but repeated for me. I had my barrel threaded locally by a well respected smith, and tried two different brakes, with the same shift.

This shift was the same regardless of factory, handloads, and different bullets.

Hope this provides some peace of mind for you.

 

[fastarget]

With and without there will be a difference. 4moa straight left on an ssg 3000 and they have stout barrels. Am i surprised , no, is 10 moa alot , yes . The saker is an effective suppressor but also on the heavy side. The heavier the weight is on a thin barrel profile the more a shift. Hang a magnetospeed on an fclass rifle barrel(1.25"), and hardly any shift, move it to my model 70 264wm with the thin barrel, and big change. Change in barrel harmonics, just like barrel tuners do.

Check all the threads and alignments and you have, now you have to zero for the configuration you intend to use for ultimate consistency and enjoy......my .02

 

[maxfly]

I run two sakers. One on my crusader 308 and one on my 300 wm. Obviously bolt rifles. On the 308 I get .1 mil right. On the 300 wm, I get .3 mils. Low. Running both direct thread.

 

[polizei1]

Mine shifted a few inches on my 8.2" Noveske 300blk and my RPR 6.5CM. 10 seems excessive!

 

[N2thermals]

I would put money on the fact that you are getting a baffle strike. It's probably very little but that's the only thing I've seen cause this much of a change.

 

[padronanniversary]

i have a very repeatable shift about 1" on my aiax and the same in my bolt guns. i moved to the keymo in anticipation for my deadair cans. But prior to movin i had no issues at all with the MADD mount and POI shift