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Posted: 10/19/2015 8:38:46 PM EDT
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I finally got to shoot my saker 762 on my precision AR, and had some unfortunate results. Accuracy went down by at least 50%. My normally MOA rifle shoots 2-3 inch groups suppressed. In the photo below the groups on the right are unsuppressed and the center and left groups were suppressed. Ammo was 77gr Nosler match handloads. Upper was a BCM SS 18in.
Is this normal? I thought suppressors were supposed to increased accuracy? What could be causing it? ETA this is with the trifecta mount and 762 endcap. Should I try a 556 endcap or direct thread mount? 
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Accuracy is aided when the barrel oscilation is "tuned" at the exact moment the bullet exits the barrel. Think of waves and troughs on the ocean. You want the bullet to exit at the peak of a wave, or the very deepest part of a trough when the barrel is not moving.
A suppressor adds weight to the end of the barrel and changes the way the barrel oscilates when fired. Try different ammo and see how it does. Might be time to work up another handload for suppressed shooting. There may be other issues going on here, but the easiest will be to see if different ammo performs better with your suppressor. I do see some vertical and horizontal stringing on the suppressed targets. Any chance you did anything to the suppressor or mount between the targets? Remove the can, or remove and re-install the mount? |
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Quoted:
Accuracy is aided when the barrel oscilation is "tuned" at the exact moment the bullet exits the barrel. Think of waves and troughs on the ocean. You want the bullet to exit at the peak of a wave, or the very deepest part of a trough when the barrel is not moving. A suppressor adds weight to the end of the barrel and changes the way the barrel oscilates when fired. Try different ammo and see how it does. Might be time to work up another handload for suppressed shooting. There may be other issues going on here, but the easiest will be to see if different ammo performs better with your suppressor. I do see some vertical and horizontal stringing on the suppressed targets. Any chance you did anything to the suppressor or mount between the targets? Remove the can, or remove and re-install the mount? I did remove and reattach the suppressor between groups, I wanted to see if POI shift was consistent (it was, 2 MOA lower) but I did notice the stringing. It was a windy day, so that could have been a factor. I did try some 55gr "plinker" handloads and got equally bad accuracy, however that was expected. I didn't think about the barrel harmonics factor, that could be an issue. the Saker is a heavy beast, and it explains the 2 MOA drop. Time to do another ladder test! |
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I've got an 18" Noveske Switchblock I use a Saker 7.62 on. (556 endcap) I've never really shot it on paper and I should. (just a quick initial 50 yard zero, groups were fine then, but too close to really know) I'm making hits on a 66% IPSC target at 300 no problem, but maybe it doesn't look good group wise on paper. Makes me wonder...that Saker is a lot of weight hanging out there, although as has been stated, it comes down to barrel harmonics.
Do paper groups matter if you make reliable hits in the field? Frustrating when this type of things happens, update if you try different loads and what the results are. |
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