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Conference foundr::firearms

Title:	God made man, but Sam Colt made men equal
Notice:	Welcome to the firearms conference!
Moderator:	PEAKS::OAKEYIN

Created:	Tue Mar 04 1986
Last Modified:	Fri Jun 06 1997
Last Successful Update:	Fri Jun 06 1997
Number of topics:	6616
Total number of notes:	49869

6615.0. "Scope adjustment" by CXOSI::TEJA () Fri May 23 1997 18:05

    I have a scope mounted on my Winchester Model 70. I had the scope bore 
    sighted when I first had it mounted on the rifle. Then I proceeded to
    sight it in. It didn't take much adjustment to get it right. I removed
    the scope recently when I glass bedded the action and floated the
    barrel. When remounted the scope and sighted it in it took a lot of
    adjustment and many rounds fired to get it back to zero. This doesn't
    concern me too much because I know that a relatively small difference
    in mounting position makes a large difference in point of aim. 
    
    What I was wondering about is....
    
    It seems to me that ideally a scope would be adjusted at a neutral
    position such that the cross hairs are in the center of the tube both 
    horizontally and vertically. Again ideally the scope would mount on the 
    rifle such that it didn't need to be adjusted from this natural point
    in order to be zeroed. We all know that this doesn't happen in the real
    world. But I was wondering if there is anything to be gained from
    trying to get as close as possible. 
    
    In other words, other than not have as much adjustment left in the
    scope after having used so much adjustment to achive zero, does it
    matter how far off of center with the tube that the cross hairs are? 
    Are the optics better in the center of lens? I am assuming that the lens 
    are concenteric with the tube. How would I go about returning the cross 
    hairs to their neutral position if it were desirable?  Did the scope even 
    come from the factory in that position? 
    
    Do I worry too much about this kind of stuff? Should I get a life?
    
    Thanks,
    d.t.

T.R	Title	User	Date	Lines
6615.1	Only if it's BAD!!	AUSS::HAGARTY	`Wed May 28 1997 21:28`	27
	Ahhh Gi'day... You are right to worry, but unless you have a severly out of alignment mount or receiver it shouldn't be a big problem. Remember that the tube inside which the adjustments are is round - much like a clock. So that if the scope is mounted with the adjustment in the middle, changes for windage and elevation are maximum. But should the mount be offset to one side, say at the 2-4 o'clock position, then the elevation will be reduced. Similarly if the scope is up at the 11 o'clock - 1 o'clock to get on elevation then the windage adjustments will be severely reduced. It pays to set the scope back to neutral settings (using a cardboard box with a couple of notches cut out) before mounting - so that if there is any latitude in the mounts this can be centered when fitting. Most scopes have about 40-60 minutes of adjustment, so it has to be out by quite a bit to notice. Optics are never as good near the edge - but on good scopes, you shouldn't notice as much - they make the scope to work over the range of adjustment, the cheapers brands might trade this off. As a general rule of thumb, 0.001" difference in receiver will make about a 1 moa difference. I bore sight all the time - put a dot on the wall about 20-25 yards away, and it will strike about 2-4" high at 100 yards.
6615.2	thanks for the info! please explain	CXOSI::TEJA	`Fri May 30 1997 13:10`	9
	Thanks for the reply. You are a fountain of information! Could youu please explain the cardboard box technique for resetting a scope to its centered position. My scope is a Tasco World Class+ fixed 6x (not the best but certainly not the worst). I would like to optimize this settup as much as possible. Thanks again, d.t.
6615.3	more	AUSS::HAGARTY	`Mon Jun 02 1997 19:31`	22
	Ahhh Gi'day... This might be a little difficult to explain. You take a cardboard box with a couple of notches cut in either side (a small mox, about 5-10" wide). Then lie the scope in the notches, which are cutout like little Vee's. Rotate the scope, while looking through it. You will see the crosshairs move in a circular "orbit". Then adjust the scope (getting the direction of adjustment right requires some thought) so that the centre of the crosshairs no longer "orbits". You have just centered your crosshairs in your scope. From memory, you will have to move the crosshairs in the opposite direction to that indicated on the tube. Just like bore sighting. After bore sighting, the best way to sight in a rifle (for me anyway), is to aim at a prominent point on a target (like a corner of a black square) and fire one shot. Then put the rifle back in the solid rest, and put the crosshairs on the aiming point. Then, without moving the rifle, adjust the crosshairs over to 2" (or whatever) above where the bullet struck. Then fire a three shot group to check - DONE!!
6615.4	Thanks	CXOSI::TEJA	`Tue Jun 03 1997 15:36`	4
	Thanks again! d.t.