Scope issue: horizontal shifts?

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Dairyboy

Dairyboy

Member
Jul 23, 2016
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Washington, United States
Athlon Helos BTR Gen2 4-20x50 having issues holding horizontal zero. Not sure how only horizontal but that's the case. Vertical stays pretty solid. I thought I had issues with my Uragan with how I held it. Did testing and had it figured out with consistent holds no issues. Shot like 10 groups in a row and zero shift so issue solved...or so I thought. Now same thing with the Prophet. However having it on 2 guns now and same issue it's not the guns. I was shooting starlings at 50yds and drilled 3-4. Took a shot at a dove at 30yds. Complete miss. What the hell? I was now off 3Mils to the left. Adjusted the scope dead on. Few shots later another miss which was stupid close. Was over a mil off to the left. Ok again fixed it. Few shots later now I'm 1.5 mils right. While vertical hasn't changed at all. 

I will be testing with my other scope but have a feeling that my scope is the issue.
 
Yeah I do test it in low winds if not any. Today there was very little. However the direction the wind was coming and I mean maybe 5mph at that point would have pushed the pellet the opposite direction. Definitely not 3 mils at 30yds. I did some testing and shot both my 4-20 and then my 2-12 Helos. Almost certain that it's the scope. I want to do more testing tomorrow but it's looking like I'm not crazy lol. There might be some slight vertical shift also. Hoping tomorrow morning to test it out. After that winds will be too strong until Wednesday or Thursday to really tell anything. I have tried looking through it with my tripod in a solid position and checking the parallax and hadn't noticed anything also. But will check again.

Randall, I have checked all screws. Everything's been tight. So I don't think it's any screws loose however always good to check. 

Bio, you know I have thought of that also. However all my scopes use tight fitting scope caps so they can't move unless my scope cap also moves. So don't think that's the issue. But maybe it's not adjusted correctly on that scope.
 
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@L.Leon both. With the misses in the field I then would shoot the pole a few times or something wherever said bird was. Then Id correct and shoot again and be off later.

I did shoot groups this afternoon I think at least 8 6 shot groups with both scopes. I'll do the same in the morning and see if I can conclude anything. My first test this afternoon I'm almost positive the scope is the issue. So I want to try it again to be sure.
 
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Dairyboy,

That nylon washer installed to tension barrel on Uragan, what is that hole in the block, just where nylon washer goes? Do we need to cut a "U" shaped slot in nylon washer to allow that hole to open to atmosphere?

My Uragan .25 and Taipan .25 both show that horizontal shift, while my Taipan .22 and Umarex Gauntlet .25 shoot like lasers. I've re-cleaned both barrels and the Taipan seems to be settling down with JSB 25.39 grain. My Uragan acts like you describe. I've ordered Hades pellets from ZANS to try. WM 
 
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Here's my shooting this morning 50yds. Top row 6 shots each with 2-12 Helos. Dead on. Bottom row same but with 4-20. Seems like it's not just horizontal? Idk it does seem to shift about some back and forth. Gun was shot in calm conditions 5 min from each other. Both filled to 270bar at the start for fair comparison. Both scopes checked for any parallax error before shooting. Also wasn't really shooting for groups but just as quick as could shoot. But could tell the 2-12 groups are much better than the 4-20 despite having a larger center dot for aim point. Would this warrant a return to Athlon to get checked out?

IMG_20220403_065622542.1648994815.jpg

 
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Pushing a tin. I'd say 400 so far. Honestly I don't clean a barrel until it needs to be showing accuracy issues. So far what I've seen between yesterday and today that my POI never changed with my 2-12 Helos. The 4-20 has shown issues on 2 guns. Tried 2 different rings. Thought I had it figured out on the Uragan but now on a new gun I'm still seeing the same shifting. Having had Uragans prior never having a POI shift before I was questioning the scope. Now I think this is confirming. I will be testing more with the 4-20 to be sure but really think something isn't quite right.
 
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Top row is low and left, and the bottom row looks high and left, I understand you did not adjust elevation. What size groups are you expecting from your gun? Also why shoot quickly and not just buckle down, to shoot some solid, deliberately sent groups? Especially if you have good conditions, for me it's difficult to draw a conclusion from your presented groups. You might also put it on one of your rimfires and test on a totally different platform. Lots of variables... I spent a good part of today shooting groups to get acquainted with my Atomic and did a little windage chasing myself. Am currently happy with my present zero.
 
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Groups not super important size wise in this test. Around half inch is all I'm caring about. Top row is all basically there. Biggest was .65" others one was .6" and middle 2 right at .5". The gun can shoot that's not the issue. I know the groups it's put down.

Top was shot with my known good scope. The 2-12. Had it for 8 months and never skipped a beat. What I'm looking at is placement of shots. You cut the squares out and over lap them that scopes poi is essentially the exact same over those 4 groups. Bottom row is from my 4-20 which I've had maybe 4-6 weeks. Can see the shifting point if cut out and stacked. Also look at 2,3, and 5. Groups shifted down and right as they were shot. Groups were more vertically spread and not as tight as the other ones from the 2-12.

As for not hunkering down again the gun can shoot. Plus didn't have much time. With a 2.5 year old and 6 week old little girls just isn't there lol. Plus church and other stuff this morning just not much time. And conditions wise I'm screwed until Wednesday. 20mph wind this afternoon. Tomorrow 25-40mph with gusts over 50mph. Tuesday also 20-30mph and gusts over 40mph. Wednesday just 5-10 and Thursday calm. After that 15-25 the rest of the week.

Here's 11 at 50yds bottom right pellet out the group was my aim point. 

IMG_20220402_162300061.1649042540.jpg


5 shots at 65yds

IMG_20220401_162945451_HDR.1649042620.jpg



 
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