Rifle Scopes Help please - Inexplicable lost zero S&B 5-25 x 56 PMII on AWSM

[FORESTBARBER]

I installed the above scope on my AWSM 338 using AI dovetail mount some years ago. It zero'd at .6 mil above the max low adjustment at 100yds. I have run over 1000 rounds through the rifle since and sent the scope to S&B service about a year ago (no charge for service - thank you Jerry at S&B) and reinstalled with same zero. No surprises when shooting after the S&B service.

I bought new AI AT 308 this summer and while waiting for Razor HD 4.5-27 optic took the S&B scope from my .338 and put on the AT using some Badger rings I had. Loved it of course. Great rifle. Happily it really likes some store bought ammo I had bought a bunch of ten years ago.

Finally rec'd Razor HD and installed on the AT with Seekins 1" tall rings. Yikes that scope seems heavy, but I like it. I don't think is as "bright" at S&B though. Still a great buy from EuroOptic.

Reinstalled S&B scope on the AWSM. With the el turret at bottom of down travel my zero is now way way off vertically - about 5.0 mil.

I have not had the AI mount off the the .338. I checked the torque on the AI mount screws and it is correct. I have taken scope off and on a couple of times - not moving mount base - using proper torque to mount and the zero repeats. I have not dropped the S&B either on or off either rifle.

I am baffled as to what has happened. I am going to contact S&B and see what they suggest, but thought I would look for insight or experience here.

Thanks,

Forest

 

[EXTREMEPREJUDICE]

Umm...........you didn't happen to reset the zero stop when you put it on the AT? Just sayin...........

 

[FORESTBARBER]

Good question, but no. This S&B does not have a zero stop. It does have an indicator when you go past one full turn. Is is at bottom of travel with this zero issue.

I will probably try putting it back on the AT and see if the zero is way off on that rifle now. I don't really recollect having to significantly adjust zero and in fact did not change the turret to zero when I ran it on the AT. I just dialed up or used reticle for hold offs.

Thanks

 

[COLOSHOOTR]

So you took the S&B completely out of the AI base, put them into different rings, then remounted it back onto the AI Base?

Any time you remove it from a mount and place it on a new mount (or back onto the old one) you will be likely to get a POI shift even with the same torque settings. You can't be 100% sure it went back into the exact same place and could be slightly forward or back in the mount from where you had it before and things can be off. Expect to re zero every time you remove the optic from it's base/rings.

Just re zero the scope and keep shooting as long as the scope still tracks right... Don't bother calling S&B unless the scope is not tracking and is broken.

Why did you remove the scope from the AI base? You would have been more likely to keep your zero if you left it in the base then just made sure you put it back into the same rail slots on the .338 after you were done using it on the AT. I've had my entire SPUHR mount off and put it back on to the rifle with almost no zero shit (.2 windage shift).

 

[CoryT]

The two turn knobs DO have a zero stop, the knob is set to stop .5 mil below zero. If you zeroed on the other rifle and slipped the scale to zero, you automatically reset the zero stop. No doubt when you mounted it in the Badger rings it needed some up to get to zero on the new rifle. You slipped the scale, and now when you remount it you can't go below zero to get back to where you were.

The scope is fine. If you are 5 mil high right now, unlock the knob and slip the scale 5.5 up. Now you can dial back to zero, then slip the knob again to get back on exact zero.

 

[CoryT]

The two turn knobs DO have a zero stop, the knob is set to stop .5 mil below zero. If you zeroed on the other rifle and slipped the scale to zero, you automatically reset the zero stop. No doubt when you mounted it in the Badger rings it needed some up to get to zero on the new rifle. You slipped the scale, and now when you remount it you can't go below zero to get back to where you were.

The scope is fine. If you are 5 mil high right now, unlock the knob and slip the scale 5.5 up. Now you can dial back to zero, then slip the knob again to get back on exact zero.

 

[FORESTBARBER]

You are probably right. I did not realize the fact the the scope bottoming at .5 mil ( I think mine does at .6 indicated) was a zero stop. I did not think I zero'd the turret when I put on the AT, but I will find out. Thanks for the input. Makes sense.

 

[FORESTBARBER]

Coloshootr

Thanks for the input. Not sure how to use quote function so will answer/reply to your input as follows:

Yes, I left AI mount on .338 and removed the S&B from that mount.

Yes, I know this but you would not expect 5.0 mil movement of zero unless something was seriously out of whack or way out of adjustment.

I can't re-zero the scope because I seem to be out of "down" adjustment on the el turret. It now seems likely that Cory T below has hit on what I have done.

My AWSM 338 and the AI one piece base/mount are the AI dove-tail. Not a picatinny rail. Not possible to mount that on the pic rail on the AT

 

[FORESTBARBER]

CoryT - You were correct, sir. I am back on zero with my .338. Many thanks.

Forest

 

[CoryT]

No problem, pretty much what I expected to hear. Enjoy!