Adjusting to the right...ever to the right.

[roj]

I'm very curious about this.  I decided to go out and experience the eclipse today by shooting a couple of hundred pellets through various guns.  When I got to the .22 Hatsun 87QE Vortex I was really perplexed.  I have a Sightron 4-12x40 AO HHR SIH-TAC scope in Weaver Quad-Lock rings on a UTG 2nd gen dovetail to picatinny/weaver adaptor.  It has been assembled now for four or five months.  Originally it seemed very accurate, but then began to waver.  (I may have re-installed the rings at some point, but can't recall...you know how that goes.)  Be that as it may...

Today, using primarily JSB Exact 15.89 gr. after several other lesser happy candidates, I found myself constantly adjusting the scope to the right...and occasionally up.  Then it would settle in and shoot true for 8 to 10 shots, and suddenly I was back off to the left for a dozen shots.  So I would adjust right again, and after a time it would lock in for 6, 8, 10 shots, and then off to the left again.  Whereby I would adjust to the right...always to the right.  Sometimes up as well, but always to the right. 

This went on for forty five minutes or so until it finally seemed to stabilize, and I was wearing out after three hours of shooting.  My question is, of all the components, the $200+ Sightron scope would seem to be the least suspect, esp. when joined with $15 rings and a $6.99 adaptor.  I had everything locked down as much as I dared.  So what  would be the most suspect component to cause this phenomenon?  The $6.99 adaptor?  But how or why does it lock in and shoot like a champ for a bit, and then suddenly go off requiring another adjustment to the right?  Esp. when all is tightened down as much as possible.  Curious.

[Roadworthy]

If everything is tight and stays tight I would guess some internal drift in the scope.  Since I'm not allowed to guess the scope has issues and everything is tight I guess the only other thing is your barrel is moving slowly to one side.

If you have open sights you could try them - or perhaps substitute a different scope and compare results.

[wimpanzee]

How are the stock screws? Breech seal?

It certainly sounds like a consistently degrading something. Do you have another scope you can test?

[roj]

The stock screws are tight.  Breech seal is an internal  thing, correct?  Not sure how to check that without dis-assembly.  I do not have another scope that's free at the moment. 

I assumed that somehow it would be the cheaper of the components...first the adaptor, then the rings, before the scope itself.  I just can't figure out how they would be moving, and always in the same pattern. 

[Techie]

Barrel bending as you pull it down and to the left?  Barrel pivot bolt or spacers loose or wearing?

[Roadworthy]

Breech seal is an internal thing.  It is easily tested by laying a piece of tissue over the breech before firing.  If firing blows the tissue it's obvious you have a leak there.  Access is really easy on a break barrel.  It's visible when you load the gun.

I don't really think that's it, though.If your mounts are tight it's unlikely they are moving.  I don't know what gun you're shooting.  With many guns the front stock screws go into the barrel.  The German guns and the English guns have a bracket screwed to the barrel and the front stock screws attach to it.  The bracket COULD be loose even if the stock screws are tight.

I'm grasping at straws here but have had it happen to me.  I really wish you had a spare scope, though.

[roj]

Turkish gun.  Hatsan 87 QE Vortex.  (Mispelled in my first post.  I was thinking Datsun.)

I will try the tissue test for the breech seal though. 

[roj]

Nope.  The tissue didn't budge.  Breech seal must be fine. 

I'll shoot it some more tomorrow and see how it does.