20 MOA Base

I have bought a Rem 700 7mm RM. The purchase price was cheaper than what I could buy a rem action for. I would like to do some long range target shooting in the future. I thought I would take it for a test drive put a scope on and see how it shoots. If it shoots good Awesome! If it doesn't I have a friend who is a smith and have the action trued and get a different barrel.

My question is, due to my budget or lack thereof due to kids going to college, I was going to buy a Pic Base. To save money should I buy a 20 moa base now even though I may not be shooting long range (3-400 yards)?

It all depends on the scope you are going to put on top of it. I have a Sightron SIII with 100 moa of travel; I don't need a 20 moa rail to go long with it. At 400 yards most scopes will have enough travel to get there. You will probably get tired of shooting 400 yards pretty quick and before you know it you will be going to 1000. I would get a 20 moa rail because you may need it in the future. It does, however, lift your scope higher from the barrel, if that bothers you.

Need? No. It's almost 100% sure that you don't "need" it for 300-400yards. 20 minutes of angle is enough to get a 7RM with mid-weight to heavy bullets out to near 1000yrds. Most good hunting scopes will have that much in them even without a canted base after being zero'd.

You use a canted base to get the elevation capability that you need to get to the distance you want. That's all. That's a thing that can only be determined based on the amount of "up" left in the scope after it's zero'd, the desired max distance of target engagement and your external ballistics with the selected load.

Start by zero'ing the rifle. Then spin the elevation turret until you run out of up and count the minutes/mils that you have left from your zero position. Now take your MV and bullet weight and other ballistics inputs and put the into your favorite ballistics calculator. See what it says you'll need to get to your max desired distance. If you don't have that much left in the optic, then a canted base is potentially on your purchase list but just as well you might need only 5 or 10MOA of cant built in. That's where you decide between things like shimming or Burris Signature Series rings or a canted base. A little bit, shim. A little more, Burris rings. A bunch, canted base. A bunch more, canted base plus Burris rings. See how that's going?

Keep in mind that some scopes; especially those on 1" tubes won't have very much total vertical adjustment range in them compared to some others so you can bone yourself by getting a base with too much cant in it. Example: 25MOA total in your scope, you zero it and have 15MOA of up left so you're 10MOA off the bottom. Add a 20MOA cant, you've just inputted 20MOA of up into the scope so you need to dial down 20MOA to retain your old zero distance but you've only got 10MOA of down left and you're now left with in a position where you will not be able to zero at the same distance as before without hitting the bottom. You'll be something like 10MOA high because there's too much up in the hardware. So, a 10MOA base would do there.

There's another factor to pay attention to. That's the issue of where scopes perform optimally optically which is right in the middle of their adjustment range. You really don't want to be zero'd all the way at the bottom of the scope's range. It leads to negative optical effects and I'm not convinced that it's not physically bad for the optic itself internally. You ideally want a setup that will get you to your max range, allow you to zero at 100yrds (my personal advice which is a separate thread) and not have the adjustment all the way at the top or bottom to accomplish either your max desired range or your desired zero range while shooting POA = POI.

I know that's a lot. You asked a much more involved question than you probably realized.

If all of your other rifle had one, as would say yes. Makes swapping scopes between rifles easier, if the need arises. If not, then no. For most shooting out to 800-1000 or so, you would not need one.

Thanks, decided to go with a 20 mm. Now on to picking a ffp scope within the budget.

My favorite FFP scope on a budget is the Vortex HS-LR!

Vortex Diamondback 6-24x 50mm Tactical appears to be a pretty good FFP scope. Maybe a little feature-poor, but for daylight hunting and long-range shooting, looks good. I just bought one after doing serious research. Not mounted on the rifle, yet. Looking through the scope, it is bright and the glass quality good. The retical (MOA in this model) is a bit weak at low power, but quite visible and informative as power increases. I didn't view through the scope at high power.

I was recently told by a gunsmith to look hard at Vortex, Nikon and the better scopes from Bushnell and Sightron. I won't pass on his suggestions on which high-end brands to look past.

saw said:

Now on to picking a ffp scope within the budget.

Click to expand...

Which i$?

I have always had great luck with sightrons particularly the stac and siii series

Sometimes people forget the principle of a canted rail. If your scope has 80MOA of total adjustment, this means that at mechanical 0, provided the mount and rings are able to hold the scope parallel to the bore, you have 40MOA down and 40MOA up at the bore. Using a canted 20MOA rail simply shifts this balance to 20MOA down and 60MOA up. Of course, if you mount the rail the wrong way, you end up with 60MOA down and 20MOA up. (This is only useful if you're shooting from a mountain top or a high building.)

For your purposes, 60MOA of up elevation should cover all your shooting needs, well, up to about a mile or two. You will probably need several MOAs to get to 100 yards, especially if all the pieces are not perfect. But once there, you will still have 50MOAs or more, provided you don't have lots of windage on the scope.

The only time you need to worry about not getting a 100yard zero using a canted rail is if the rail has more cant that one half of the adjustment range. Say your scope has 30MOA of adjustment range, 15Down/15Up. A 20 MOA rail will shift that to -5Down/35Up.

For me I like a cant. So when I dial up my reticule stays in the center of the lense. I like it to stay in the middle 75% of the lense. Seems to have better picture. Especially with budget scopes. Just my experience.

Why would it be bad to have the scope bottomed out while at 100 yard zero? I mean I wouldn't need to have any down adjustment because I wouldn't need to adjust for any thing closer then 100 yards. If you have your scope zeroed and have half of your adjustment up and down then I would think your just wasting half of your scope not using that bottom half.