Originally Posted by peterh
If you would suspect that this might be a problem: there's an easy test you can do yourself.
- Take a fairly large paper target at short range, say, 8 yards, and fire off three shots. Start at your zero position for 8 yards somewhere at the top left. This will be your aim point for the entire excercise.
- Then, dial all the way through your range up to where you come off highest (somewhere in between 20 and 30 yards I suspect), and shoot three times, aiming at the same point.
- Now dial a full turn to the right, shoot three times, again aiming at the same point.
- Now dial the elevation turret back to 9 yards, leaving the windage turret untouched. Fire three shots, still aming at the aim point mentioned in step 1.
- Lastly, dial the windage turret back to the left a full turn, and fire off a shot.
If your turrets work well, you should now be back to exactly
where you started, and the four groups you shot should form a nice square.
I've done this with all scopes my wife and I have or have had, and there was only one that malperformed - a very crummy 4x20 scope. All others (more than a handful of Swifts, a Falcon, two BSA Platinums, a BSA 8-32x44, and an Optisan El Cheapo 3-9x42) stood the test with flying colours.
Thanks for that will have to give it a try
Its not actually what i was getting at, I was wondering what actually moves in the scope to cause shift and why is it a step change, if it was simply expansion surely it would be gradual unless something "clicked" out of place as the expansion reached a certain point
The comment of Rich, we are lucky its not much worse, rings true for me, the engineering must be exceptional not to get more shift than we do
From your description of the "square test" and the results that only one scope has failed is it not too easy, should it not be at longer range to magnify any errors - if everything passes not a real test