Strange POI shift
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All Springer/NP/PCP Air Gun Discussion General
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Optics, Range estimation & related subjects
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Tpatner412
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only1harry
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Strange POI shift
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Topic: Strange POI shift (Read 724 times))
Mtl_Biker
Marksman
Posts: 465
yes
Real Name: Eldor
Strange POI shift
«
on:
February 20, 2017, 03:58:21 PM »
Using a Hawke Airmax scope (new series, with etched reticle, not wire) on my HW50S .22 spring gun...
I had the scope zeroed at 22 meters and kept the gun in my living room by the patio door, usually laying it down on a soft carpet. My feede... uh, "target" is out at 22 meters, and I also have a bent spoon spinner on a tree at the same distance. I've shot maybe 1000 shots there and I always hit the spinner and I've been very happy with the gun and scope.
Suddenly I couldn't hit the spinner anymore. And the gun hadn't been bumped nor had the scope adjustment changed. First one or two times, I thought I must have had too much coffee or been under too much stress. But the problem persisted. Finally I stuck a paper target out there so I could see where the pellets were going and to my surprise they were way down and to the left. Consistently. I re-zeroed the scope (took about 30 clicks up and 6 to the right) and now another 50 shots later, it's back consistently hitting the target.
Velocity of the gun seems to be the same (didn't chrony it, but it hits the same way and has the same penetration on wood as before).
What could possibly have happened? What would make it go off zero by that much? Almost as if someone had turned the turrets and changed the zero but since I live alone and no one else touches the gun, it's something else.
If I'd zeroed the gun and taken only a few shots with it and then the zero changed, I'd suggest that maybe the internal springs in the scope had been under tension and then the tension released. But gee, it's been about 1000 shots with perfect zero and then suddenly it's off.
Any ideas?
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Montreal, Quebec
AA S510 Xtra FAC Ultimate Sporter *CARBINE* .22
CZ200S Green .177 w/Hawke Airmax 30 SF 8-32x50
Feinwerkbau 800 Evolution Top
AA S400 MPR FT .177 w/Hawke Airmax 30 SF 6-24x50
Steyr EVO 10
Weihrauch HW50S .22 w/Hawke Airmax 4-12x50
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Crosman P1377 & P1322
BenjiHunter
GTA Senior Contributor
Posts: 10692
Semper ubi, sub ubi.
Real Name: Stefan
Re: Strange POI shift
«
Reply #1 on:
February 20, 2017, 04:14:07 PM »
I assume you used the same pellets as before.
Clean the barrel and see if POI goes back to what it was.
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Surahammar, Sweden
Webley Patriot .25 . 30FPE
Benjamin 392, Leapers 3-9X32 BugBuster. 12FPE
Mac1 Steroid 392, Leapers 3-9X32 BugBuster. 22FPE
Mac1 1322 FT, Hawke Sport HD IR 3-9X40 AO. ?FPE
Rats shot 2016 = 40
Rats shot 2017 = 85
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Roadworthy
Honorary GTA Moderator
GTA Senior Contributor
Posts: 9706
yes
Real Name: Thomas
Re: Strange POI shift
«
Reply #2 on:
February 20, 2017, 04:28:46 PM »
When a similar thing happened to me, replacing the piston seal solved the problem.
If you have a chronograph try using it to compare speeds when the gun hits properly to when it's low.
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Near the Southern Coast of Washington State
Real knowledge is knowing the extent of one's ignorance.
condor22
Expert
Posts: 1798
סם
Re: Strange POI shift
«
Reply #3 on:
February 20, 2017, 05:58:36 PM »
Gremlins or poltergeist, the moon was full an exorcism is needed. Time to try a different, known good, backup scope. Several consecutive days.
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Danville VA
Scotchmo
GTA Senior Contributor
Posts: 2343
Real Name: Scott Hull
Re: Strange POI shift
«
Reply #4 on:
February 23, 2017, 01:54:52 AM »
Scope might have shifted back slightly and hit the stop. When it shifts it can sometimes throw the sight off. Tighten the scope a little more to make sure it is secure.
Make sure the stock screws are tight while you are at it. Then recheck zero.
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Los Osos, California
Morro Bay Airgunners
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GTA
»
All Springer/NP/PCP Air Gun Discussion General
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Air Gun Gate
»
Optics, Range estimation & related subjects
(Moderators:
Tpatner412
,
only1harry
,
GTA-Airgunner
) »
Strange POI shift