I bought a used RRA NM upper. I am trying to figure out if it is 1/4" or 1/2" aperture. It isn't written on there. I was wondering if there is a way to find out?
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RRA National Match Aperture
- Thread starter tacticalpanda
- Start date
Are you asking how much MOA you get with each click? A 1/2 minute base screw is a coarse thread and a 1/4 is pretty fine.
Mathematically, you can figure it out with a micrometer; 1 moa is about .006" of movement in a rear sight. So 1/4 sights would be .0015" and 1/2 would be .003". So, a full revolution of 25 clicks would be .0375" of movement in 1/4 minute sights and .075" of movement in a 1/2 minute sight.
It's way easier just to look at the thread pitch to determine values. Google up "1/4 1/2 rear sight difference" and it should show a pic of both screw threads.
This is assuming RR accomplishes 1/4 moa sights by changing thread pitch instead of just adding another detent.
Mathematically, you can figure it out with a micrometer; 1 moa is about .006" of movement in a rear sight. So 1/4 sights would be .0015" and 1/2 would be .003". So, a full revolution of 25 clicks would be .0375" of movement in 1/4 minute sights and .075" of movement in a 1/2 minute sight.
It's way easier just to look at the thread pitch to determine values. Google up "1/4 1/2 rear sight difference" and it should show a pic of both screw threads.
This is assuming RR accomplishes 1/4 moa sights by changing thread pitch instead of just adding another detent.
Awesome. Thanks for the info. It looks like they are 1/4 minute as they have what appear to be the small threads. Google brought the picture right up.
