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Posted: 12/4/2011 3:31:54 PM EDT
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I was out trying to refine my zero with my Galil 7.62mm ARM at a new range. I ended up bottoming out my front sight to get it on paper and then switching to the 500m rear sight and was able to zero at 100yd with a half turn off of the bottom. My preference would be to have my 300m sight an inch or two high at 100yd and, when I get an opportunity, attempt to refine a 200m zero on the 300m sight. I'm sure that I've had it zero'd better before and am generally perplexed at the massive shift in vertical POI; the sight is obviously low in the front sight globe.
I don't think that ammo is the primary issue since almost everything that I've used is 147/150gr FMJ and 168gr HPBT printed pretty much the same. My new theory is that, the range that I have been zeroing at has a wooden portal that I have been able to push my bipod into for a steady hold and recovery; great for stability. Could it be that pressure on the bipod is shifting the POI? It feels like there might be a little flex at the trunnion when I put some good pressure on the bipod. Anyone have a similar experience with an ARM? Feedback would be great before I blow another 40rds playing with it off of a rest instead of the bipod, and bipod with no forward pressure, to test my theory. I suppose this is a cry for help and potentially a warning for others. I will post again after my next range trip. Chops |
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Range time complete. I was at the same range in very similar conditions as my earlier zeroing session; ammo was the same Win Q3130. I was able to produce a 12" vertical and 6" horizontal variance in POI just by putting pressure from the rear against the bipod on a solid front stop. Initially I had been pushing hard forward into the bipod, but I assumed a good rested bench hold, bipod folded, and a good amount of pull straight back on the forearm which brought the point of impact back up 12" and to the right 6". I rezeroed using the rest by switching back to the 300m rear sight and bringing the front sight back up 1 1/4 turns.
Interesting experiment for me anyway. Now I know that excessive forward pressure on the bipod will bring my POI lower. Chops |
| I personally don't use a Bi-pod I shoot with a bean pillow or a vise if I want to make sure its not me doing the moving....My shooting buddy shoots with a Bipod on his Ak and also on his AR and his shots are all over the paper....If you can learn to balance the pressure your putting on the barrel its a lesson learned. |
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