POI Shift Problems Seneca Aspen

[ShadowShot]

Hello all.

I have a problem someone might be able to help me out with.  I just recently purchased a Seneca Aspen .22. This is the coolest gun ever to me. It is the newer upgraded model that should have the pump lockup fixed.

Im shooting .22 JSB 18.13gn. I have checked my curve and adjusted my hammer spring all the way in and then 1/4 turn out for my prefered velocity. I shoot three times at my best pressure, 3200 Psi. Once im done with three shots, 12 to 13 pumps and Im back at my start pressure. One time my string was 914, 915 and 913. That was my best string. For accuracy, I have pellet on pellet at 25 yards. At 50 yards, I am getting a group smaller than a quarter. Can't ask for much better.

My problem is this, after I zero the rifle, shoot it for a while and put it away. The next time I get it out, the POI has shifted. The last time it was 8 clicks low and 3 clicks off to the right. Once I re zero it, I'm back to surgical accuracy.

At first I thought I had a bad hawk scope. I put a Nicon on and re zeroed, Lazer accurate until I get it out again. POI had shifted again but consistently hits exactly the same spot every time as if I had zeroed it there. I put a third scope on, it was a bug buster. Same results, accurate but have to re zero after it was put away. A quick search here on GTA resulted in a hit. https://www.gatewaytoairguns.org/GTA/index.php?topic=164940.0
I followed this advice and found both the shroud fittings were loose and stripped. I repaired this and also had to adj the barrel band so it would be center of the barrel with the shroud off. It was leaning hard to the right and touching the shroud slug. I also found and tightened the four screws at the base on the pump.

With everything good and tight, barrel band aligned to the barrel and with consistent shot string pressures, I still come away with the same problem. Laser accuracy but once put away and taken back out, the POI shifted again to a new spot.  If I don't adjust the scope, it keeps hitting at the same new spot like it was zeroed to it.  [It does not always shift to the same spot when put away.]

Outside of having a gremlin in my closet who is adjusting the scope every time I put it away, I have no Idea what is going on now. Very frustrating. Any ideas?

Shadowshot.

I still love the gun, I just want a divorce from the gremlin.

[Madd Hatter]

I had the same problem with mine when I first received it a year and a half ago. It was the bushings inside of the shroud were loose and the set screw threads were stripped. I went 1 size larger and was able to tighten it down. Mine didn't even wait for over night to move. When I was trying to zero the brand new scope I'd adj it and then it would be off in another direction. My avatar was shot at 25 yards and was a 10 shot group.

[ShadowShot]

Thank you Robert. I  have addressed that problem without success. I did have the same issue, loose stripped bushings. I drilled new holes in both bushings and retreaded with a tap. I've tightened them down good and snug with no movement that I can disern. Still havening the issue after doing that.

BTW, excellent shot group. Congrats.

[Madd Hatter]

Do you lean your rifle against the wall over night or lay it flat in a hard gun case? Have you checked the barrel set screws in the receiver?

[ShadowShot]

I was leaning it against the wall but then tied to see if laying out flat on a bench would prevent the shift. That didn't help.

 I did check the barrel screws in the beach, the three across the top. I even removed the barrel to see if it was bent, straight as an arrow. Put it back in, all the screws snug.

It's got to be something simple.
I love how accurate it is when it don't shift. It's lights out accurate.

[Madd Hatter]

Try shooting it with out the shroud end cap.

[ShadowShot]

Well it looks like the gremlin has gone away for now. I came home yesterday and checked the rifle with 3 shots at 25 yards, still holding zero. I tried it 3 different times today, still good. I'm propping it back up in the corner and will try again tomorrow. I guess it finally settled in after I tightened everything I mentioned. Strange, we will see tomorrow. Thank you Robert.

[ShadowShot]

Well, I spoke to soon. I took it out today to shoot. First few shots were ok but started s shifting after about 12 shots. It would shift to a spot and shoot tight groups there. I finally emailed AD for an exchange. Will have to see what they say. The only thing I can come up with is that it shifts after it warms up a little. Maybe from the sun warming it up or lead friction.

I will try to pull the shroud off and try it a couple days while I'm waiting on an RMA. I have service tomorrow night so I can't do much with it tomorrow. We will wait and see.

Update:
It's definitely a heat issue. I took it back out just now and it is hitting dead on the money like it was before the poi shift before the above mentioned 12 shots.

When I took the shroud off, it is touching the left side of the barrel band and no way to adjust it. I zeroed it with the shroud off. I will see what it does now.