Zeiss Conquest DL Help

[tmwtrfwler]

I normally lurk on this sight but at the moment I'm in need of some advice. Question is related to a Zeiss Conquest DL 3-12x50 with a 60 reticle (illuminated duplex). Each adjustment is 1/3 MOA

The Zeiss scope I posted about last week was dialed in like a dream last deer season and last weekend (the 16th). I was hitting a center of a 10" gong at 200 & 300 yards every time. This weekend (the 23rd) I couldn't hit a 10" gong at 200 yards. Then I shifted to the 100 yard target to check it's zero(I zero'd the rifle at 100 yards, 2" high, for dead on at 200 originally). Saturday was 5" low and 5" right. There was no POI / POA shift due to the suppressor so that is ruled out. The rounds were the same as last weekend. The weather was almost identical. The rifles precision was still good with tight groups. The accuracy was out the window.

Some facts about the scope that may be of help:
- Sitting in Talley Rings
- Sitting on a Nosler M48 Liberty 300 win mag
- The elevation only had 1 MOA shift up remaining when I checked the zero (elevation had plenty of room)
- I remember it being odd how little adjustment I had left when I originally zero'd the gun last year
- I found mechanical zero of the scope when I got it last year and sighted in from there
- The rifle was not bumped, dropped, kicked, etc. to knock it off zero between last weekend and this weekend
- Factory Ammo, same box - 8 rounds last weekend - 12 rounds this weekend - well spaced out as we were shooting several other rifles so no walking due to temps.
- I should've done a box test but wasn't thinking

Possible issues:
- Could it be that with the elevation up so high that the reticle is boogerd up? Stretched too tight or broken?
- Would Talley rings not hold? Everything was still tight and no noticeable shift on the scope (slide marks, scuffs, etc)
- Could a Zeiss Conquest DL have poor enough quality to not take a 300 win mag? Strange it would give out after a season but who knows.

I removed the scope from the rifle last night so I could start all over. I went back to the mechanical zero. It has 114 clicks of elevation and 112 clicks of windage. those are now set at 57 and 56 respectively.

Should I sight it in again and if I run up towards the top limits of elevation again, take the elevation below the mechanical zero a good bit so that it's not up so high?

Any advice welcomed. I've not had a scope ever do this before. Pretty strange.

 

[tmwtrfwler]

Think I found the issue. The forward most base screw is stripped. The next one on the same base was partially. You can see the silver part of the screw and how it's smoothed out. Interestingly the fromtnbase didn't move a bit when I tried but I suppose my attempt is not as effective as the kick of a 300 win mag. Now I need to find replacement screws.

 

[JaoeyP]

If you ask Talley, they may replace those screws, but your threads on the rifle may be ruined. If they are you might have to drill and tap them up to 8-40. I had to do this on a Mauser once. Certainly is a lot beefier!