Rifle Scopes Problem with my scope....what could cause this?

[Lofty]

I have a Bushnell ERS that I had an issue with today.

So about 3 weeks ago I went shooting, shot a little F Class match at 500 yards. Rifle was dead on, shot a 199 on my first set with 9 in the 10 ring, so everything was dead nuts zeroed. I went home, took the rifle out of my bag and put it in my safe and havent touched it since.

This morning I go shooting and I couldnt get on steel at 525 yards....couldnt figure out what was going on. I went back to 100 to check my zero and found I was 1.2 mils high and .6 mils to the left. My zero stop was bottomed out and everything seemed fine but obviously my zero had shifted significantly, for no reason.

I hadnt dropped the rifle, not touched it since I shot 3 weeks ago and it was shooting perfect.


What the heck?

I re-set the zero and it seems to be OK right now. It tracked all the way out to 1000 yards and back to zero several times.......working flawlessly again but Im now wondering what I may have done to cause that.


Any ideas?

 

[918v]

Loose scope base?

 

[Lofty]

That's the first thing I checked. Rail is integral to the action and the Rings are all torqued to spec. Exactly like the day I installed them.

 

[LawnMM]

Loose rings, base, etc, shooting from a bench vs prone or vice versa

 

[918v]

What firearm? Maybe you have bedding issues?

 

[Lofty]

I don't think that's it. It's a Defiance action in a KRG chassis. Just checked the torque on the action screws, they're fine.

I don't get it. After zeroing it again it's putting one bullet after another through the same hole.

I can see how different positions make small changes but not 1.2 mils difference.

 

[bkw1911]

Was the scope new? I had a similar issue with my mark 6. I had busted up the original turret on a rock and sent it in to leupold, they put a new turret on it and then I sighted it in. Next time I went out I was pretty close to 1 mil high and a half mil left. I think it just needed to settle cause I resighted it in and haven't had any shift since then. That was over 6 months ago and 500rds and 5 matches.

 

[bzg4cf]

After shooting at 500 and before finding it was off, did you turn the turrets at all for any reason, like turning back to 100 yard zero then readjusting before shots were fired next time out? I usually turn my scopes back to 100 yard zero before putting it away, and I found a similar problem one outing when the elevation knob slipped. When the turret was pulled up to allow adjustment it actually felt loose or wobbly. I believe I did not have the two locking/set screws tight enough. I had a very similar symptom to your description.

 

[918v]

It's time for a ...........