I have a scope with an adjustable objective for parallax. After adjusting the parallax out and firing 2 or 3 rounds the parallax needs to be adjusted again. Question is, is it possible for something to be loose causing this? I called the manufacturer and was told it was not possible for this to be happening. Thank you for any information about this.

Is the scope moving from it's original markings or just not in focus?
I had a scope on an air rifle that would gradually move from a higher power to a lower. So I would say yes that the objective is moving.

Hip

Parallax adjustment wanders under recoil.

I believe the objective is fine threads that moves the objective lens in and out!

I would see the manuf. is bullshitting you.

A small piece of tape should hold it in place---I know , Not Cool!

Hip

One thing I have discovered is that though both parallax and picture focus can be corrected with this adjustment, they might not occur at the same distances at the same time; nor do either necessarily occur at the settings shown on the dial. If focus did come accurately at the dial reading, we would not need rangefinders.

As to your question, perhaps you could put some grease on the the threads to stop the adjustment turning so easily.

I have heard that air gun match shooters use their AO for range finders! Don't remember what kind of match though but I think it was like an archery 3D match.

Hip

quote:

Originally posted by Phil Brousseau:
I have a scope with an adjustable objective for parallax. After adjusting the parallax out and firing 2 or 3 rounds the parallax needs to be adjusted again. Question is, is it possible for something to be loose causing this? I called the manufacturer and was told it was not possible for this to be happening. Thank you for any information about this.

Unless the actual ring is moving (in which case you have a cheap and/or defective scope) my guess is your barrel is getting hot and creating mirage, which makes the view a bit fuzzy.

How far off is the parallax? and how are you determining it is off in the first place?

If it's a knob or ring, you should be able to use a pencil mark to prove it's moving. If you mean the adjustment ring stays but the internals move - well that's different.

I'm thinking the internals are moving and the ao ring isn't.

If it is a Leupold send it in with your complaint of the apparent problem and they will fix it or replace it.

If it is some other brand get rid of it and buy yourself a Leupold.

Good advice stonecreek .thanks to everyone for the replies.