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Old 17th January 2016, 11:13 PM
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RobF RobF is offline
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Join Date: Mar 2010
Member of: Southampton Buccaneers, Parkstone, South Dorset
Location: Poole, Dorset
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Originally Posted by GaryB View Post

I've been going through the motions of setting up my new Sightron SIII scope and one I've found is it ranges very well in all temperatures & light conditions (so far) so I'm really happy there.

I've been setting up & establishing my click chart and had them pretty well set and this was carried out outside in about 12 degree temperature and modest light. Tonight I went to Pete's indoor range as I had spare time and thought I'd double check everything indoors but everything was quite a few clicks out and at 50 yards there was no consistency in shot placement, it went off at about 40 yards.

Is it pretty normal that the cold (it was about 1 degree outside) can affect point of impact and this is where you have to "learn your scope" or being new to this am I missing something that could help me?

There's a number of possibilities.

First the scope is changing it's rang finding under temperature change, and it's not telling you the same range as before to dial in. Shooting a consistently known target in varying conditions noting the temperature helps work this one out.

Another is that your gun isn't sending the shot down the range at the same speed. A good chrono using consistent lighting that doesn't interfere with it will show that under varying temperatures.

Another is that the gun and scope aren't pointing the same way they were under differing temperature (and if wood, humidity). Been there and done that as well.

By eliminating the variables, and monitoring those you can't, you can get a bead on what is doing what when, and what can or can't be done about it.

This is why you'll find temperature devices on a lot of FT rigs, and also why some may swap gear to seek to minimise what they can. Some scopes do it more than others, some at different temps, some gradual, some switch, some aren't that bothered, and some shooters never shoot in a wide variety of conditions.

My advice is get a handle on what you think could be happening with some range time, push the rig to see the changes, then learn to cope while finding out if they can be minimised. It does take some confidence to rely on what you think may happen, but once you start being able to match predictions with observations it becomes second nature.

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