parallax question

[favload]

Ok I am looking for the best way to know that I am getting the most out of my optics and shooting style. I have heard about 12 different ways i should be adjusting my scope for target shooting and the next day I will hear/read something different. My eyesight is poor, I dont shoot with my dominant eye, and i also shoot with a 4x booster which complicates things. I can usually shoot in the 2's out to 300yds and I have not changed my load in a few hundred rounds. However, some days my groups come apart. I am wondering if its my optical set up?
Here are some common things I have heard:
1. Don't worry about the paralax setting. Focus everything so the image comes in clear. Its all based on your eyes.

2. Set your focus knob and leave it alone from then on and then set your parallax. Your crosshairs should be clear and the image should be slightly blury.

3. Set your parallax to the indicated range and set your focus from there.

4. If your seeing groups dance around the target but your 2nd and 4th,or 1st and 3rd I guess) shoot group in the same hole it can be a parallax problem. Can someone please tell me if there is any truth to this.

In short what do the experts say about the above?

 

[NateHaler]

IMO, you must remove parallax to ensure your head position,i.e. slight variations from shot to shot) does not affect your results. Or, shoot a rail gun and forget about head position and contact with the rifle.

 

[gunnermhr]

Follow this link,

http://www.longrangehunting.com/forums/f18/parallax-vs-focus-1988/

It is the best description of paralax I've seen

 

[holstil]

The link that gunnermhr referred you to explains it to a T and a xyz for that matter. I didn't read all completely as describing most anything can be exhausting.
This may be reiterating, but if not its worth knowing.
You can tell if parallax exists by simply moving or nodding your head side to side or up and down while looking at the target through the scope. You can even see the apparent error. As a foot note, the object/target can, and in some scopes will remain a little fuzzy while achieving a parallax free image. Most important, is to remove any parallax and allow a fuzzy image. Keep the reticules focused.
In fact, I just crank the objective adjustment while looking through the scope moving my head, every time I change distances.
My guess is if your shooting in the 2s at 200 you don't have parallax.
Jim

 

[Eddie Harren]

If I could,'usually shoot in the 2's out to 300yds', I wouldn't change a thing, on my scope.

 

[favload]

Thanks for the help. VERY useful.