my post here indicated a failure of a Zeiss Conquest 4.5-14x50 on a recent stalking trip:
Regardless of the cluster@@@@ of logistics and balls I may have to go through to get it repaired in the US I needed to to prove the scope was at fault and nothing else so I planned a trip to the Morton Range today
- 300WM and faulty scope complete with both brake and mod
- Spare known to be good scope (trusty Nikko Stirling 8x50!)
- known accurate rifle - trusty .17M2 (no point blasting CF rounds to prove a point when you can do it with cheap RF ammo)
Shoot the 300wm with chocolate scope - prove one of them doesn't work
Shoot the 300wm with known good scope - prove 300wm shoots OK
Shoot the .17M2 with the good scope it has on it and then the chocolate scope to prove the chocolate scope is the issue
Before going I decided to take a closer look at the mounts and turrets
Mounts are solid, not moved in years
On removing the retaining screws and pulling the turret caps I noticed this difference:
This in itself is not the issue as checking where in the thread range they were sitting
Elevation - 3/4 turn up, 2 turns down (elevation sitting higher with room to stretch)
Windage - 1.5 both ways
What I did find is the centre tapped screw in the centre of the windage turret that the cap retaining screws go into is totally loose and at least 1-2mm high out of the brass.
I am assuming as it is central to the adjuster collar and the threaded aspect the turret pulls down into that it is also fundamental to the vertical adjuster staying in one place!!
Anyway, I tightened up, the only way to do this is to refit the outer turret cap without the retaining screw, use it to stop the inner turret rotating whilst tightening the screw through the retaining screw hole (got all that!?)
So scope rebuilt and refitted.
Get to the range (more on that later)
Rifle on front and rear sandbags, solid as a rock
Target set at 50yds just in case the chocolate scope can't manage a 12MOA target!
1st shot - 5" low, 5" right
as rifle is solid I go for a one shot zero adjustment to move crosshair onto hole. seems to be tracking ok
next shot on the sticker, two more shots one in the same hole one next to it!!
looking good so far...although it is 50m!
Next up same test with muzzle brake:
First one scares the shizzle out of me as the blast catches the inside of the box I am shooting in and blows a plastic aerosol cap next to me clean off the bench onto the floor behind me!
The noise is incredible
That one may be a flyer!...
I adjust my underpants and try again
POI shift is 2 case lengths up and 1 case length right (no ruler!)
3 shots in two holes....
(flyer to the left!)
scope seems to be holding zero...albeit at 50yds
Decide to let it cool down with some .17M2 plinking, have brought it may as well use it!
Zipping through 18 rounds in a couple of minutes, good practice, removes the potential to flinch and reminds me how much I love this round
Starts a little high but a few tweaks mid way through and it is bad news for bunnies (or hare )
next up the 300WM 180gr SP's
3 in similar POI as the 208gr, nice little cluster
180gr through muzzle brake shows same POI shift and similar cluster
Mod back on
Target out to 100metres (ballistic app says a 50m zero is 1" high at 100m)
(I am given a timer by Paul to show I only have 7 minutes remaining of my 60 which has whizzed by!)
1st one I aim for the wrong sticker and lose it in some existing holes
2, 3, 4, 5 go OK but I am struggling with heat haze off the mod, having to blow it away and then shoot before it comes back!
Still happy they are all within an inch or so though as 6 days ago I couldn't have hit a 6" plate!
two more then a quick adjustment of 3 clicks down 3 clicks left to bring it to as near as dammit a 100m zero
(i wrote 2 but it was actually 3!)
buzzer goes off. time to pack up
So either I have temporarily/permanently fixed it and identified either a poor manufacturing element or some ineptitude on someone else's part
it something has popped back in by sheer fluke!!
Either way I am delighted as I had visions of pound notes flying out the door in shipping and handling and being bent over by some agency, company, homeland security etc etc!
I left a message for Gary at Zeiss UK to see if he can confirm if that loose screw could result in a shotgun pattern and wandering zero.
Will confirm when he gets back to me.
moral of the story ....if you have a scope that works, leave it alone and don't go buying new ones!!