parallax

[Luke45]

never really thought of parrallax alot before untill today, i would just focus the scope and shoot. Today a wierd thing happend, after a morning of shooting switching between 3,4 and 600 yards, i went back to the 600 yard line and forgot to focus my scope and left it on 300. i missed the 6" gong by about 1.5 feet 2 times in a row in different places. then realized my parralax was adjusted for 300 not 6. then i properly focused it and hit it 5 times in row. could the focus being off really make me miss by that far?

[BillPa]

Well sure. Set you rifle in the bags then without touching it move your head slightly side to side and up-down. If the AO isn't set the crosshairs will dance all over the place. If they do adjust the parallax until they stay stationary on the POA. Don't pay a lot of attention to the graduations other than for getting it close, they may or may not be 100% accurate. I have a few scopes with a white label on them with lines drawn on them for different yardages, they don't line up with perfectly with the graduations.

Bill

[Alleycat72]

Depends on your head position, but yes. Always move your head in a small circle and see if the reticle moves on the same plane as the target.

[foxx]

I've only read this, but my understanding about parallax is it only causes a problem if you do not line up properly behind the scope. (Most people do not). I am sure I cannot as well. The problem is not that the focus is off, it is that you are not looking straight thru the lenses and so you're kinda like looking thru the surface of lake water and getting a distorted view of the target. If you can be certain to look straight thru the scope, you won't be so far off.

plus what Bill and AlleyCat said. :)

[Luke45]

thanks for the info guys! much appreciated

[pdog2062]

parallax problems will also create two distinct groups on the same target.

[BillPa]

parallax problems will also create two distinct groups on the same target.

Or a lousy group altogether.

Lighting conditions will also throw you a curve ball. I learned that lesson the hard way at W-Port one day. There was little wind low at ground level but the clouds were moving pretty good up high. When I looked at my target I had two distinct 7" groups, shots 1 thru 4 and 10 in the lower one, 5 thru 9 in the high one. I had fired the high group when the sun was behind a cloud and the low one when it was out.


On the vertical plane, light intensity can lead to aiming error. When shooting with low intensity of light, compared to the light intensity while zeroing the rifle, the shot goes high. On the contrary, when shooting with greater intensity of light, compared to the light during rifle zeroing, the shot flies low. I generally use an adjustment of 0.1MIL just at 100m, and 0.2 or 0.3 MIL over 600m. Translating those distances to yards and inches, that is about ½ inch at 100yds and about 7in at 600yds

Bill

[TC260]

I've only read this, but my understanding about parallax is it only causes a problem if you do not line up properly behind the scope. (Most people do not). I am sure I cannot as well. The problem is not that the focus is off, it is that you are not looking straight thru the lenses and so you're kinda like looking thru the surface of lake water and getting a distorted view of the target. If you can be certain to look straight thru the scope, you won't be so far off.

That's like saying the brakes on my car work fine as long as I don't go over 35 mph. It may well be true but the better solution is to fix the brakes.