grouping worsens as scope power increases?

[jdefranc938]

I have been told that variable power scopes are not as consistent as a fixed power scope. However, my buddy and I went out a little while back to my range with his Marlin 22LR. He has a Simmons 3x9 scope on it and we were using Federal ammo. When sighting in at 50 yards on 4x, the group was approximately 0.5". When we started playing around and increasing the magnification of the scope, the group kept increasing in size. When we got to 9x, it was approx a 2" group. Now I know that some will say it's only because it's a Simmons and that's the reason it isn't consistent at different magnifications. But I have several Simmons 4x scopes on my other 22's and they are phenomenal. Is this a brand issue, or is there something else I don't understand?
One of the reasons I am bringing this up is because I want to put a scope on my new 10/22 build. I wantto put a Leupold on it, either a VX-I 4x or a VX-I 2-7x. So I'm trying to see if anyone can explain this phenomenon to me...
Thanks in advance guys!
Jeff

[lanenebraska]

It's called Parallax, or the lack there of.

With a .22 at 50 yards and a Simmons that is parallax corrected for 100yards, the more you increase the power, the worse your groups will be. Most of your 4x scopes (.22 cal scopes) are set for 50 yards parallax, and will perform very well at that distance.

Scopes with an Adjustable Objective for parallax correction can be fine tuned to most distances from 25yards to infinity.

So don't sweat the variable scope for your 10/22, just make sure it can be adjusted for 50yards or get one with an A.O.

[jdefranc938]

Thank you!
The VX-I 2-7x doesn't have an adjustable. But the parallax is set for 60 yards. So if I'm shooting at something that's 25 yards (squirrel, target, etc...) will I have the same problem? Or will I just have to leave it on a smaller magnification like 2 or 4x?

[BabaOriley]

Taken from 2009 Leupold Rifle Scope Owners Handbook:
Understanding parallax
Parallax is the apparent movement of the target relative to the reticle when you move your eye away from the center point of the eyepiece. It occurs when the image of the target does not fall on the same optical plane as the reticle. This can cause a small shift in the point of aim.
Maximum parallax occurs when your eye is at the very edge of the exit pupil. (Even in this unlikely event, our 4x hunting scope focused for 150 yards has a maximum error of only 8/10ths of an inch at 500 yards.)
At short distances, the parallax effect does not affect accuracy.
(Using the same 4x scope at 100 yards, the maximum error is less than 2/10ths of an inch.) It is also good to remember that, as long as you are sighting straight through the middle of the scope, or close to it, parallax will have virtually no effect on accuracy in a hunting situation.
About fixed parallax distance scopes
Any fixed focus optical system can be adjusted to be parallax free at only one distance. Most Leupold scopes are adjusted at the factory to be parallax free at 150 yards. However, there are exceptions:
1. Leupold rimfire scopes are set to be parallax free at 60 yards.
2. Leupold shotgun/muzzleloader scopes are set to be parallax free at 75 yards.

[BabaOriley]

Here's a good link too.

Off topic, but this is another great link. Best example I've seen showing why all rifles should have a bubble level on them.

[Glen]

I use 4x Nikon ProStaff's on my 22 rimfires. Never had a problem with any of them.

[Rick in Oregon]

Many of my rimfire 22LR's wear Leupold 3-9X EFR's with AO (Adjustable Objective). This allows precise dialing of the parallax and eliminates any sighting error at any range you'd use a 22LR for.



This 10-22 was the Ruger Target Model, but I was given an Acculite carbon fiber barrel for it by the manufacturer, and now it's my "truck gun", as it's nice and short, swings easily inside the cab, and is deadly on our ground squirrels out to as far as I can hit them using WW Power Point HP's. This rifle has killed literally thousands of ground squirrels, and is my primary "drive-by" gun while on the ranch property. You just can't argue with the 10-22 for reliability and reasonable "rat accuracy", and the adjustable objective makes hitting at any reasonable rimfire range just about a certainty.