Rifle Scopes Proper procedure for adjusting side focus/parallax

[Joe L]

I have a problem getting the parallax right on my new Bushnell 3.5-21x50 DMR scope. (I don't think there is anything wrong with the scope, just with the way I'm adjusting it.) If I adjust the side focus from close to far and then take a few shots, the parallax seems to change slightly with each shot, and the groups are bad. If I adjust it from far to near, parallax is stable.

Is there enough clearance in the scope internal mechanism to allow movement on recoil? Is the proper procedure to rack the adjustment out to infinity and then come in to the target distance and never go back out or change directions?

This is the first bolt gun and side focus scope I've owned or shot, and my inability to hold parallax is really a problem on paper at 300-500 yards.

Joe

 

[maggitas]

Re: Proper procedure for adjusting side focus/parallax

Taken from Premier site:

Removing parallax from the scope:



1. Look through the scope at a target and move the head up and down slightly
without moving the rifle.

2. If the reticle seems to bounce downwards then you have to turn the knob for a
closer distance setting. If the reticle appears to bounce up then the knob must
be turned to a setting for a farther distance.

Adjust for closer distance Adjust for farther distance

3. Continue to move the head up and down slightly until there is no movement of
the reticle against the target. The scope is now parallax free at that distance.

Note: Sometimes, however this is not always the case, the image clarity will also be best
when there is no parallax.

 

[BigJimFish]

Re: Proper procedure for adjusting side focus/parallax

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Is there enough clearance in the scope internal mechanism to allow movement on recoil?</div></div>

Yes, this is referred to as lash. Older Leupold Mark 4's were somewhat well known for having a lot of play. This is why many guides recommend adjusting from far to near and not the other way. Here is an old blurb written about it by USO. It's kind of ironic since they recommend their Ergo system in it and they no longer make that system.

 

[scudzuki]

Re: Proper procedure for adjusting side focus/parallax

I briefly owned a used HDMR (H59) and it had about 30 degrees of deadband in the parallax knob. To focus to 100 yards from minimum distance, I had to turn it up to 300. From max distance, I had to turn it down to 100.

The original owner of the scope wanted it back and Scott at Liberty Optics had that SMOKIN' deal on new DMRs with G2DMR reticle, and the one I bought has no lash at all.

Yet.

I have not noticed the focus drifting on the new scope.

Joe