Can I rely on an old scope for hunting?

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I’ve bought an old scope that looks clear but I’m unsure of exact click values... how can I check it’s working correctly? Chris Parkin replis

Q: I have bought an older but still very clear riflescope, but I am unsure of the exact click values on the windage and elevation dials. I would like to use the scope but want to check that it is working correctly before I trust it with any hunting plans.

CHRIS PARKIN replies: If you have mounted and zeroed the riflescope, you will probably already have a good idea of which way the dials send the bullet on target, and by how much, but the simplest way to check things out is to zero the gun and then with a large target, wind perhaps 30 clicks ‘up’ (winding it as far as you can improves the accuracy of your test) and shoot a group of at least three rounds, to negate the chance of you throwing a shot. Then measure the distance that the point of impact moved on target at that range, say 100 metres, and if 30 clicks moved it perhaps 28-32cm upwards, you can assume the clicks were 1cm at 100m or 0.1mRad. If 28 clicks moved it 7” at a 100-yard range, they would be ¼” clicks (or MOA near as, damn it)! It never hurts to record your settings and dial around in all four directions to perform a ‘box test’ and don’t worry too much if your maths gives you a value of 11mm per click or 3/16” of an inch; it is probably just down to the relative accuracy and precision of the gun and target measurements. Unless dialling to shoot at long ranges, it’s not really that important. If everything shifts back to zero when you return to the original settings, the scope is probably okay. It is also beneficial, if the scope has adjustable magnification, to shoot three rounds at each magnification onto one large target and see if they all hit the same area – damaged scopes will soon throw up a flag here, and if the point of impact does shift at different settings, this needs further investigation.