View Full Version : front sight height

April 22, 2009, 10:28 AM
Have a Mossberg 100ATR rifle in .308. I stalled a peep sight that simply mounts on the rear Weaver base. Need to have a front sight installed. How do I determine how high the front sight should be to work with the rear sight? I have selected a front sight base but need to know how high the bead should be. They come in different heights.

April 22, 2009, 02:36 PM
Well, I might approach it this way. You should be able to center the peep in the middle of it's adjustment range, then measure how high the center of the peep is above the centerline of the bore (i.e. center of the striker on a bolt action).

Then move out to the muzzle. You should be able to do some simple math and figure out how high the bottom of your front sight bases dovetail is above the bore. 1/2 barrel diameter at the muzzle + front sight base height. Now take the bore center/aperture center dimension, and subtract the frontsight base to bore height...following me?

Another way is to sandbag the rifle somewhere safe where you can look at a distant object through the bore, then cobble up anything, a toothpick in clay for instance, until it allows you to sight through the bore and through the sight at the same object. Measure your ersatz front sight, there's your front sight height.

April 22, 2009, 02:48 PM
I got it. I'll try the math method. I'm an engineer. In case you're wondering what sights I am installing, they are from newenglandcustomgun.com. Click on peep sights and look at the one that mounts on a Weaver base. Then click on front sights and see the regular front sight base. The beads are seperate and come in different heights. The only other thing I am wondering about is that the diameter of my barrel at the muzzle is .625. They do not list what barrel diameters their front sight fits on and they will not answer an email. Typical for the gun industry.