A day at the range - Check you scope mount screws!

I finally finished off a flooring project at home on Saturday, so was earned a well deserved Sunday range session.

Been shooting my 7mm-08 a bit more lately at the range, and had some pretty good success with the 150gr Hornady Precision Hunter ammo, but as ive got more Hornady Whitetail in the safe i thought I'd get that sighted in over the weekend.

My best groupings for the precision hunter showed that the rifle can shoot so was keen on seeing how the whitetail rounds would go.
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Sighting in at 100m i really struggled to get a good grouping. Two shots close, then a flier.
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I was putting it down to all sorts of things, not least of which my own shooting on the day, until i swapped rifles and started sighting in my kimber 308 with the VX-R 1.25- 4 scope on it. At 100m i was getting better accuracy than with my Z5 2.4-12 BT swaro scope on the 7mm-08.
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Now, I've got a idea, that I'll swap scopes over and use the Z5 on the better performing rifle so i start removing the rear talley lightweight mounts on the 7mm-08 and to my surprise the screws on one side of the rear mount are loose. I can't explain it at all, but almost no resistance to remove them. Righto, that's got to be the issue!!!
I re-torque everything up to 20lbs and get back to the 100m range.
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Not great shooting, but in the right direction at least.

Off the the 200yd targets for a zero. Not really happy with that to be honest either as i find the larger targets a bit hard to shoot at for some reason.
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I make some adjustments and go back to just a plain old 1 inch black square on the back of an unused target. Aim small, miss small apparently.

This time i apply a bit of light downward pressure on the scope settle in and fire two shots.
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I fire two more, after a break and get a similar grouping, but a bit higher. Nothing wrong with windage, but i did feel that was aiming was a bit higher than the first two shots.
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Right, final adjustment of 2 clicks down for my set zero. Pulled to left with that one, but elevation spot on now.
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Next I give it 16 clicks up and take aim at the 330yd gong. 2 shots almost touching, centre of target. I'm happy once more.

I validate a bit further at the 440yd gong and its in the centre again, but slightly to right (bit of left to right wind so not surprising). Happy days!!!!

Now i just need to replicate my shooting om some deer this weekend!