Scope Question

[DapperDan]

I think its 30 ft if i remember correctly.

[dustoffer]

The adjustable objective isn't for clarity -- that's the eyepiece's job. The AO is to adjust the parallax so that when you are on a steady rest, and slightly shift your head up/down or left/right, the crosshairs don't appear to move in relation to the target. If your target is a known distance and the AO is properly adjusted, when you move your head, the crosshairs/dot will stay on the target. If it isn't properly adjusted, they will appear to move. If it isn't adjusted within a reasonable amount, the image will be unclear, but you should focus your scope using the adjustable eyepiece.

[trophy8]

If it were me, i would buy a scope with single crosshair and has adjustable windage and elevation turrets. learn the drops of your bullets at certain ranges. Then adjust elevation with your moa clicks. But, unless you can shoot no more than a 1 inch group at 100 yrds and practice at extended ranges to truly know your rifle, i wouldnt shoot further than 400-500 yrds max. The margin of error becomes way to much. The amount of drop in an average bullet between 600-700 yrds can be as much as 50 inches. My 270 is 41.3 inches of difference. A 308 dead on at 100 yrds has close to 360 inches of drop at 1000 yrds. Thats 30 feet!!!!!

this is exactly what i chose to do.... first time out, i knew my drop at 500.... 6" plate, made my elevation adjustment and BANG!! silence.... ding!! HIT!! works like a charm.... 500 was pretty easy, but im shooting for 1k.... its not gonna be so easy

[bboswell]

Following because I see lot of bad info here and want to see a knowledgable person correct it.

[trophy8]

Following because I see lot of bad info here and want to see a knowledgable person correct it.

if you know its bad then you should know how to correct it

[Cuz]

#1) Oh man, now my head hurts! lol. Not understanding WHY the mildots would change and the main crosshiar doesn't when adjusting power?? The mildots or rings on a bdc ARE fixed and on the crosshair right?

#2) Dustoffer, I believe you are correct. I think the AO is for crosshair clarity and stability at all yardages...

[Cuz]

That shouldnt matter at all. I shoot at 3x and 9x out of my kahles and its dead on every time. What may be happening is that holding the cross hairs steady at 100 yrds at 9x is not as easy as on 3x due to higher magnification. Magnification should have nothing to do with point of impact.

If you are shooting a varmint reticle (reticle with hashes marked for extended ranges) the hashes under your main cross hair will change their zero with different magnification. Example would be if you are sighted in at 100 at 3x and the next hash down is dead on at 200. If you go to 9x then first reticle is still 100 but next hash is no longer 200 but would be zeroed for over 200 bc of the change of relative distance between horizontal reticles due to different magnification. Clear as black paint I know!!

I'm sorry Sir but it does. Out of AT LEAST two different Nikons (prostaff & monarch), 2 different Leupolds (rifleman & varix iii) and one Bushnell (Elite) that I have shot. Moving the power up/down does effect the center of the crosshairs. I know it's not me/the shooter because I'm using a deadsled and basically line it up and squeeze off. No way for me as the shooter to be messing it up. Regardless of the power setting.

[trophy8]

#1) Oh man, now my head hurts! lol. Not understanding WHY the mildots would change and the main crosshiar doesn't when adjusting power?? The mildots or rings on a bdc ARE fixed and on the crosshair right?

#2) Dustoffer, I believe you are correct. I think the AO is for crosshair clarity and stability at all yardages...

its really hard for me to explain easily.... i dont use them, but it was just explained to me a few weeks ago in depth..

ill see if i can find some info for you to read

[trophy8]

http://www.chuckhawks.com/mil-dot_scopes.htm

[Mike D]

I'm sorry Sir but it does. Out of AT LEAST two different Nikons (prostaff & monarch), 2 different Leupolds (rifleman & varix iii) and one Bushnell (Elite) that I have shot. Moving the power up/down does effect the center of the crosshairs. I know it's not me/the shooter because I'm using a deadsled and basically line it up and squeeze off. No way for me as the shooter to be messing it up. Regardless of the power setting.

Dustoffer's post is correct. The AO or "side focus" if you have that instead of AO, is to adjust for parallax in the scope. As you change magnification the mirrors move inside the scope and can misalign and cause your POI to shift, but in reality it doesn't you just have to dial everything back in alignment. Like he mentioned if you have your AO set for 200 but are shooting at 100, if you move your head, the crosshairs will appear to move as well. The reason you believe your other scopes move when going to higher power magnifications is because if you don't have AO or SF, then most scopes are set at a fixed parallax adjustment for 100 yards. Anything closer or farther than that will introduce parallax and if your head is not in the exact same position each time, it will cause you to be off target. This usually comes more into play at higher magnification and with lesser quality scopes.

Anything over 9-10x magnification is a must to have AO or SF IMO.

Thoroughly confused yet?

I could go into why Mil Dot and BDC scopes are only accurate at a certain magnification range but that opens a whole nother can of worms regarding first focal plane and second focal plane.

[BigTex.308]

Dustoffer's post is correct. The AO or "side focus" if you have that instead of AO, is to adjust for parallax in the scope. As you change magnification the mirrors move inside the scope and can misalign and cause your POI to shift, but in reality it doesn't you just have to dial everything back in alignment. Like he mentioned if you have your AO set for 200 but are shooting at 100, if you move your head, the crosshairs will appear to move as well. The reason you believe your other scopes move when going to higher power magnifications is because if you don't have AO or SF, then most scopes are set at a fixed parallax adjustment for 100 yards. Anything closer or farther than that will introduce parallax and if your head is not in the exact same position each time, it will cause you to be off target. This usually comes more into play at higher magnification and with lesser quality scopes.

Anything over 9-10x magnification is a must to have AO or SF IMO.

Thoroughly confused yet?

I could go into why Mil Dot and BDC scopes are only accurate at a certain magnification range but that opens a whole nother can of worms regarding first focal plane and second focal plane.

It can get kinda hairy there




Ike

[Cuz]

Dustoffer's post is correct. The AO or "side focus" if you have that instead of AO, is to adjust for parallax in the scope. As you change magnification the mirrors move inside the scope and can misalign and cause your POI to shift, but in reality it doesn't you just have to dial everything back in alignment. Like he mentioned if you have your AO set for 200 but are shooting at 100, if you move your head, the crosshairs will appear to move as well. The reason you believe your other scopes move when going to higher power magnifications is because if you don't have AO or SF, then most scopes are set at a fixed parallax adjustment for 100 yards. Anything closer or farther than that will introduce parallax and if your head is not in the exact same position each time, it will cause you to be off target. This usually comes more into play at higher magnification and with lesser quality scopes.

Anything over 9-10x magnification is a must to have AO or SF IMO.

Thoroughly confused yet?

I could go into why Mil Dot and BDC scopes are only accurate at a certain magnification range but that opens a whole nother can of worms regarding first focal plane and second focal plane.

So, Mike, what you're saying is AO and SF actually increase accuracy when it comes to adjusting the power? Not just helping you see the crosshairs better?

[Mike D]

So, Mike, what you're saying is AO and SF actually increase accuracy when it comes to adjusting the power? Not just helping you see the crosshairs better?

The short answer is yes.

https://www.google.com/url?sa=t&source=web&cd=1&ved=0CCwQtwIwAA&url=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DJrFj2zR0mdI&ei=MM7DUI2kF8nFqQGB5YDQCw&usg=AFQjCNH7ZaD4BJp4O6EoBk6CEkJHkr4UCQ

[Cuz]

The short answer is yes.

https://www.google.com/url?sa=t&sour...Bk6CEkJHkr4UCQ

Good video, Mike. Thanks!

[Roger_Roger]

The adjustable objective isn't for clarity -- that's the eyepiece's job. The AO is to adjust the parallax so that when you are on a steady rest, and slightly shift your head up/down or left/right, the crosshairs don't appear to move in relation to the target. If your target is a known distance and the AO is properly adjusted, when you move your head, the crosshairs/dot will stay on the target. If it isn't properly adjusted, they will appear to move. If it isn't adjusted within a reasonable amount, the image will be unclear, but you should focus your scope using the adjustable eyepiece.

This ^^^^