Buying mounts for my scope, I'm a bit confused.

Free-2-Flow

I'm buying mounts for my Ruger, I thought I needed high mounts which are 42mm - 52mm Objective and that's what It says on the pack.

My scope is 6 - 20 x 50

Here's where I'm confused.

What am I measuring?

Is it the Inside Objective? (50mm lens)
Which means I was right.

Or the outside Objective (63mm Steel)

Thanks.

Cass

To pick the rings you need to measure the height off the barrel needed.

Usually what i do is;

• Take the diameter of the objective lense, in this case 50mm.
• Add 3mm for the width of the housing (twice as its circular) and 4mm for the minimum height off the barrel.
• That gives 60mm.
• Split that which gives our height from the barrel to the centre line of the scope tube. So 30mm.
• Now measure the height of the rail/base (if you have one). If not skip this part.
• Say its 7mm.
• Take the 7mm from the 30 mm leaving you with 23mm and thats the height of the rings you need.

Once you have this number you simply need to find out how the manufacturer measures their rings.

For example some measure their's from the base of the ring (the flat piece that sits on the rail/receiver) to the bottom of the curve (where the tube sits). Measurement B in the picture.

Some measure from the base of the ring to the centre of the ring diameter (centre line of the tube if you will). Measurement A in the picture.

Of course you might find some measure from the part of the ring that sits on the rail/receiver to the bottom of the curve.


Once you have the height you need and find out how the manufacturer measures their rings then you pick the right height for you from that manufacturer. Measurement C in the picture