Centering reticle

[Dallas Jack]

I have my scope mounted and sighted in for 100 yds. For some reason I decided to see how much adjustment I had and where in the adjustment range I was. Anyway I mounted a stud type (with grid) boresighter in the muzzle and noted where on the grid the recticle was. I then turned the elevation and windage to each extreme and noted the position on the grid.

I found I had 36 inches of travel for each. I then adjusted both windage and elevation 18 inches from the extreme (should put the reticle in the center) and noted the position on the grid. Well I compared the position with what I had noted when I started and I was back to the same grid I had started at. This means my reticle was centered when the gun was sighted in. Accually I looked at the turrets (turrets had been set to 0 when the gun was sighted in at 100 yards) and I was off by 1 inch in elevation an 3/4 inch in windage. The grid is 1=4" at 100 yards so the difference was my not being able to split the grid closer. But close enough.

Anyway I used the mirror method as a check (hold a mirror up to the objective and adjust your reticle to match the reflection.) and It was way off. Just for a check I adjusted the elevation to match with the mirror and ended with very little up adjustment. Something like 4 inches.

I have read in several places, probaly on different sites to use this method instead of counting clicks to recenter a recicle.

Now for my question. Why did the two give different results? I know the first method using the grid is correct. I counted the movement accross the grid. Is there something wrong with the way I am using the mirror? Any ideas?
Dallas Jack

[oneoldsap]

I always center the reticles on scopes that I mount . I have found no need to bore sight after doing this . The fact that your reticle is within an inch of center in each direction verifies that your scope mounting holes are drilled in almost perfect allignment with the bore of your rifle . Your scope bases and rings are nigh onto perfect too ! That is a very good thing , your scope will will draw the maximum light that it is capable of with a centered reticle . I don't know anything about that mirror business you mentioned , or what the use of it would be . Is there any smoke involved with that mirror ?

[hooligan1]

+1 for oneoldsap on this one, and usually this is the normal step in proper scope mounting. I usually go to my dungeon where neery a sound can be heard, and count clicks, I also use a pen and paper.. I count to 25 and put one talley down at the end of it all you can center your scope and properly mount it and check down the bore to see if their close at say 25 yds. This is also unpractical for autos, unless you have seperated upper from lower... Any way where did you hear about a mirror trick? I used to work all my teenage summers at a busy Gun-shop and have never ever not once heard of that one.. That's why we all love this forum!!!!! P.S. You had it sighted in why mess with it? The rifle doesn't shoot according to bore-sight it shoots according to your 100 yd adjustment.....of course there's a difference...

Thanks for coming!

[Dallas Jack]

I always center the reticles on scopes that I mount . I have found no need to bore sight after doing this . The fact that your reticle is within an inch of center in each direction verifies that your scope mounting holes are drilled in almost perfect allignment with the bore of your rifle . Your scope bases and rings are nigh onto perfect too !

When I mounted this scope I had centered it first by counting the clicks. The rings were centered using a lapping bar and then lapped to maximum contact. In other words care was taken to insure things would be correct.

I don't know anything about that mirror business you mentioned , or what the use of it would be . Is there any smoke involved with that mirror ?

I visit and read many different gun forums. The "mirror" method had been mentioned on several. It is used to recenter a reticle. As I understand it you hold a mirror to the objective and adjust the reticle until the reflection overlaps. Apperantly I did it wrong and was looking for a responce from someone that uses this method to explain what I was seeing.

P.S. You had it sighted in why mess with it? The rifle doesn't shoot according to bore-sight it shoots according to your 100 yd adjustment.....of course there's a difference...

I was doing this to see how much adjustment there was left after sightin. It had nothing to do with the difference between bore sight and final sightin and everything to do with what was left for dailing the scope for distance.

I hadn't tried to dial in the scope (for more elevation) before and did this just to find out how much adjustment was left. Thought it would be a good idea to find this out at home instead of when I needed it for shooting at something.

Thanks for the info though.
Dallas Jack