Minute of Angle to Miliradian Scope Base

When setting up your rifle and selecting your scope, rings, and base, something to always think about is the cant in your scope base. You will see 0, 10, 20, 30, and even 45 MOA bases. What this does is angle the front of the scope downward to give you more travel in your turret. Doing so will allow your scope to be setup in such a way that you will be able to shoot out to farther distances. All of my rifles have at least a 20 MOA scope base. My .308 has a 60 MOA base. Both .22s have 20 MOA. My 300 black out bolt action has 45 and my 338 LM has a 30 MOA scope base. If you're unsure or don't really understand MOA, then go with a 20 MOA. And if you don't need a 20 MOA, get it anyway. I would rather have it and not need it, than need it and not have it. I can say for sure, I have never not needed it. I shoot my 300 blackout and .22 (using subsonic ammo), at 500 yards; talk about bullet drop! When I shoot the 300 blackout at 500 yards, I have to dial up 21.3 Mils. But, with my .22 shooting subsonic at 500 yards, I have to dial 32.5 Mils. Really I have to max my elevation out on my turret and hold way over. There are two potential problems you can run into. First, you can have too much cant/too much MOA in your base. This will cause you to not be able to set a 100 yard zero. Depending on your scope's elevation, adjustment, and caliber, this could be a problem. The second is if your rifle doesn't come with a base. This will cause you to play the guessing game, and potentially cost more money if you realize you wanted a 30 moa base instead of a 20 moa base. I don't have a good solution for the second potential issue, other than if you're not sure, get a 20 moa base. But, I can help with the first. Assuming your rifle has a scope base, mount your scope and snug it down. It doesn't need to be perfect, just eyeball it. This is a test to see about how much elevation is at the bottom of your scope once zeroed. Do a rough zero by looking down your barrel and having the scope and barrel aiming at the same point. Keep track of this zero point on the elevation turret. From this point, you need to turn the turret until it bottoms out and then count the mils. Lets say, for this example, you had 15 mils before it bottomed out. This gives us an idea of how much cant we can put in our base. You don't want to be zeroed at the bottom of the travel for a few reasons. One, you will be looking through the edge of the lense, and it will be blurry and your sight picture will be oval instead of round. Second, if you need to dial down, you won't be able to because you're already at or near max. So, lets leave at least 5 to 7 mils minimum; for this example, let's go with 7. That leaves us with 8 mils we want to add to our useable elevation in our turret. Ok, well now what how do? We calculate how many mils an moa base gives us. Here it is: Every 5 Moa in your scope base gives you about 1.45 mils. So if we have 8 mils, we want to go with a 25 or 30 moa base. 45 moa = 13.05 mils 40 moa =11.6 mils 30 moa = 8.7 mils 25 moa = 7.25 mils 20 moa = 5.8 mils 15 moa = 4.35 moa 10 moa = 2.9 mils 5 moa = 1.45 mils I will typically try to get as much MOA in my base as I can. I push it to the point where, if I can only dial down 1 or 2 mils, I'm ok with that. I only shoot 100 yards when sighting in or doing load development. Other than that, I start shooting at 500 yards. I'll shoot at 200, 300 and 400 to confirm my dope at those ranges. But typically, I go straight to 500 first on a 4 inch plate. I hope this helps. The Overwatch