Getting rid of parallax

[Custom Eyes]

Had my .308 all dialed in with a 9X scope. Nice and consistent. No problems at all. That scope had fixed parallax. Bought a new 18X scope to get more range. This one has a parallax adjustment. For the life of me, I cannot get this thing to shoot consistently. I can set up, dial it in fairly quickly, but as soon as I change my shooting position or reload and set up again, I'm off by up to 10" in any direction. The parallax dial is pretty dead on. At a 200 yard distance, the target is steady at the 200 yard dial setting. I think part of it is that with this scope, I'm having a hard time getting my eye centered and a clear field of view and reticle. Any tips or ideas?

[rickn]

I doubt paralax is going to move 10" at 200yds. Check rings and bases for tight, or could be the scope. Try it moving the vertical adj. Up6-8",then back to zero to see if it returns to zero. Move it and shoot, move it back and shoot.

[Phil T]

rickn is most likely correct.

[Custom Eyes]

Originally Posted by rickn

I doubt paralax is going to move 10" at 200yds. Check rings and bases for tight, or could be the scope. Try it moving the vertical adj. Up6-8",then back to zero to see if it returns to zero. Move it and shoot, move it back and shoot.

I'll give that a shot and see. Everything is rock solid. First thing I checked, and multiple times. Pretty sure it's some sort of parallax or focal plane issue though. What convinced me today was that I had 3 8x11 targets set up side by side to try to sight it in again. Laying on the ground, shooting off a bipod. Went for the right target first. Was about 5" off on the first shot. Dialed it right in with a couple shots. Went for the left end target, still laying in the same position and was back off by at least 6" on the first shot. Dialed it in again on that target. Went back to the right target and that was off now. Went back and forth like that through 60 rounds. Even if I left the gun sitting in the same position and just put another magazine in and stayed on the same target, I was off again when I repositioned and took the first shot.

Is it possible to over-zoom the scope? I had it up to 18X at the 200 yards. No problems with the old scope on full power. I could have it set to 9X at 30 or 150 yards and it was dead on consistent, taking the rise or drop out of the equation.

[rickn]

No, can't over zoom . If the parallax is off, the cross hairs will move as you move your head, but not that much. I'd bet on a bad scope.

[grizzley]

Originally Posted by rickn

I doubt paralax is going to move 10" at 200yds. Check rings and bases for tight, or could be the scope. Try it moving the vertical adj. Up6-8",then back to zero to see if it returns to zero. Move it and shoot, move it back and shoot.

X2!

Here's something to try:
With the scope on a rest, with or without the rifle, place the crosshairs centered on a target and look through it and nod your head slightly up and down, and then slightly side to side. If the crosshairs seem to move quite a bit, try changing the FOCUS slightly to see if the movement diminishes.
I had never heard of doing that, but learned about it several yrs. ago from one of the guys I know who is quite active at a local bench rest shooting club.
Doubt if that will solve your problem though, but maybe worth a try.

[Custom Eyes]

Originally Posted by rickn

No, can't over zoom . If the parallax is off, the cross hairs will move as you move your head, but not that much. I'd bet on a bad scope.

That's what I'm starting to think. But, if I do move the parallax dial out of range, I get some pretty significant movement. It's pretty steady set at 200 yards on the 200 yard setting. For the heck of it, I set it to 0 and 400 yards, and on both, the reticle would move completely on and off the paper without much head movement at all. Literally, I can move the reticle 20" on the target. That's why I was wondering if the zoom might be exaggerating the parallax, if parallax was the issue. I also cranked it up to 1000 yards on the parallax setting, and it wasn't really any worse than the 0 or 400 yard setting.

[Phil T]

Is the parallax adjustment at the front or objective end of the scope or is it done with a dial on the side?
Just a guess, but I'm thinking the more convenient side dial could introduce another complication that may break.

[Custom Eyes]

Originally Posted by Phil T

Is the parallax adjustment at the front or objective end of the scope or is it done with a dial on the side?
Just a guess, but I'm thinking the more convenient side dial could introduce another complication that may break.

Front. The whole front turret turns to adjust the parallax.

[Phil T]

I have a couple scopes with parallax adjustment and a ring at the front of the objective lens is turned. Is that what you meant when you wrote front turret?