Calculating Required Ring Height

[SDJim]

Eventually I'll be getting my precision rifle, once I get it, I'll be mounting my SS 16X42.

It has a 30MM tube, and the dia including the fwd sight cover is 54MM.

So half of 54 is 27MM, subtract 1/2 of the tube diameter gets me 12MM.

Add in the height of the scope base 7-10MM?? gets me to 19 - 22 MM of stand off.

Soooooooooo . . . if I'm using rings that measure from the bottom edge of the scope ring to the top of the scope base, I should need rings measuring anywhere from 3/4" to 1"?? Dependent on the type of scope base I get.

Am I over complicating things here, am I way off base??

[SemiAutoSam]

I would measure from the center of the ring to the top of the mount.

[Prc329]

Go here

http://www.midwayusa.com/midwayusa/staticpages/charts/ring_height.htm

[surprised]

Eventually I'll be getting my precision rifle, once I get it, I'll be mounting my SS 16X42.

It has a 30MM tube, and the dia including the fwd sight cover is 54MM.

So half of 54 is 27MM, subtract 1/2 of the tube diameter gets me 12MM.

Add in the height of the scope base 7-10MM?? gets me to 19 - 22 MM of stand off.

That sounds right, except for adding the scope base height. Why is that needed? If anything, you could subtract it, if the bell overhangs the scope base, since in that case it is equivalent to higher rings. And if the bell sits above the base, you wouldn't need to add it either. [Also, you may need to account for things like the clearance between the bell and the barrel, iron sight clearance if you leave them on, if the forend wraps portrudes above the barrel, etc.]

But I don't think I understand it either, because... (see my comment after the next quote)

Go here

http://www.midwayusa.com/midwayusa/staticpages/charts/ring_height.htm
I recently bought some rings, and I checked this chart. It makes no sense to me. Using the methodology you outlined above, many of the entries call out for rings that are too short. The rings I bought did fit, but only because I ignored the table.

[Prc329]

I used that a couple of times with great success. 50mm objective called for medium rings and my 40 called fit low. Both fit and was comfortable for me to shoot. Now if irons are in play that is a whole different ball game.

[Fjold]

Understand also that your base mounts on top of the receiver and the front bell of the scope is mounted above the barrel as it tapers down from the shank diameter to the barrel diameter.