Shiming help! (please?)

[azroaddust]

I have installed an older style B Square forward mount on my Mini. I like it becasue it sits high and I can still use my peep sight (Ranch model) if the batteries ever go south. HOWEVER>>> because of its heighth, I cannot adjust my Aimpoint down enough. I'm using a LazerLyte bore sigting tool ($39.50 from WalMart), and I can only get within 2 or 3 inches at ONLY 25 yds and run out of adjustment. Once I get it at 25 yds I'll go to 50 then to the range for the finite sighting.

I have recentered both adjustments and am going to start over. I THINK what I need to do is shim the rear mount? If this makes sense, how many thicknesses of beer/pop can aluminum would be good to start? Any and all comments, instruction, etc. from anyone will be most welcome. I have never had to shim a scope or red dot before. :(

Thanks in advance!!!!

[Tailgunner]

Raising the rear will raise the POI, raising the front will lower the POI.
Mount spacing (in inches) divided by the distance to target (in inches) will get you the amount of shim required to change the POI by 1" (use 3600 for 100yd, 1800 for 50yd, or 900 for 25yd).

Example: If your ring / mount spacing is 3.6" than .001 of shim will move you about 1 inch at 100yd.

[azroaddust]

Originally posted by Tailgunner@Sep 11 2005, 05:38 AM
Raising the rear will raise the POI, raising the front will lower the POI.
Mount spacing (in inches) divided by the distance to target (in inches) will get you the amount of shim required to change the POI by 1" (use 3600 for 100yd, 1800 for 50yd, or 900 for 25yd).

Example: If your ring / mount spacing is 3.6" than .001 of shim will move you about 1 inch at 100yd.
Thanks. I think I've got it. If I RAISE the Rear, that Raises the P O I. I think that's what I want since the current POI is 2-3 incles Lower than the Aimpoint Red dot. So I am to bring the POI UP to the sight rather than trying to lower the sight to the current point of impact (sort of something like that?)

[Tailgunner]

Impact up or dot down is the same thing, just two ways of expressing the same thing.

[azroaddust]

Originally posted by Tailgunner@Sep 11 2005, 10:49 AM
Impact up or dot down is the same thing, just two ways of expressing the same thing.
Yes, unless you are having a major mental retard day like I am. I thought about this and realized that I'm all messed up. I've never had this problem before, and as embarassing as it is, I was adjusting the wrong way.

I'm sighting HIGH now, so I should be turning to RAISE the POI. My backwards thinking had me adjusting DOWN which lowers the POI making thinks worse. Correct? If so, I probably can remedy by just adjusting properly.

Gads, and have done this numerous times at the range with both rifle and pistols!

Thanks for helping a humbled PU member! :o

[Tailgunner]

Happy to be of assistance, and I've chased my tail more than a few times doing sight-ins.

[azroaddust]

Originally posted by Tailgunner@Sep 11 2005, 12:39 PM
Happy to be of assistance, and I've chased my tail more than a few times doing sight-ins.
Yes, we all do strange things sometimes, even though we know better. I needed a whack on the head and you did it most kindly.

THANK YOU! Got it sighted in close enough for the daylight. Tonight I'll go for 50 yds in the dark, scare the heck out of my neighbors and probably end up with a SWAT team at my front door, but at least it will be ready to got to the range for final adjustment. (If I stilll own it by then)!

Many thanks again! :)