Zeroed scope then next trip out it was off

[rigatoni]

I'll start this by admitting that it could be something I did wrong, but will ask anyway if anyone has experienced the same thing.

A while ago I zeroed a scope on the day, all fine, packed it up and it has been back in the safe untouched since then.

On the next trip out it was somehow off. Had to adjust it an inch or two in each direction.

Now I'm the only person with access to the safe, so no one else has been tinkering with it.

I didn't drop it on the way home, back it on the safe, have anything fall on it or anything else.

Any ideas on what might have happened? Cheers.

[rigatoni]

Forgot to say, once zeroed again it held it for a day of shooting so there doesn't seem to be anything wrong with the scope as far as I can tell.

Cheers.

[Baldrick314]

Did you check all screws to make sure they were tight? If it held it's zero all day this probably isn't the cause but doesn't hurt to be sure.

Was there a vast difference in temperature/ humidity between the two trips? Did anything change with your ammo? Different brand / new handloads?

[Member-Deleted]

Did you clean it after sighting it in?

[Bark]

Maybe just a bit of an off day the first sighing in?

Pull a few shots or get a few overlapping flyers it could look like a zeroed group when really it was a few off shots.

I find shooter error is to blame for 99% of things

My own shooting included

[rigatoni]

Thanks for response guys.

1) Scope mount screws and the rest are all tight. Mounts are tight on the action etc.

2) Erm, can't really say about the temperature or humidity. I think a cold day the first time around, and a warm day on the last trip out. Nothing crazy though... I didn't go from Alaska to Nevada or anything like that...

3) Same ammo as before, same batch of cartridges even.

4) Gave it a full clean and oil after the first shoot before storing it again.

Thanks.

[VICHunter]

I suppose there could have been a crown or odd bit of uneven barrel fouling that was throwing it out the first time around? Cleaning it fixed it up?

Doesn't sound like you have a fault with your scope though really...

[5Tom]

I'll go with weather and environmental conditions as long as the rifle and ammunition were the same.

Humidity, temperature and air density will effect point of impact in one way or another.

[reddog]

What is the scope?

If the barrel is not free floating and it's a timber stock it could be the change in temperature/humidity

[rigatoni]

Hi guys,

Went out again this weekend and had no problems.

The stock is timber and there is one touching spot, maybe that was the problem with some swelling.

I need to float the barrel I guess.

I'll do that and keep track of it on a few more trips, scope seems solid though. Just humidity and swelling hopefully

Cheers.

[reddog]

Check your action screws too

[rigatoni]

Yep they were all fine too.

I think you were probably on the right track with temperature and that.

Will keep track of it. Thanks again