Rifle Scopes Help deciding whether or not to get a scope mount with 20 (or more) moa cant...

[cuz]

How do you decide whether or not to add cant to your scope base? I have a Ruger Precision Rifle (in 6.5 CM) that comes with a 20 MOA canted rail. I'm planning to mount a Minox ZP5 5x25x56mm scope to the rifle using an American Defense AD-Delta mount. Should I get a mount with an additional 20 MOA cant built in? Or not? Why?

How do you decide whether or not to add cant to a mount, and how much to add? What are the pros and cons? For now, 95% of my shooting will be from 100-600 yards, and I know I don't need it for that. I guess I'm wondering that if I need to buy a mount anyway, should I just get the one that adds 20 moa and then I won't ever have to worry about it? Is there any downside to having too much cant other than possibly not being able to zero at 100 yards? I know the extra cant will allow for further shots, but will it hinder shooting from 100-300 yards?

It seems the more I learn, the more I need to learn...

Thanks,
Cuz

 

[GBMaryland]

You can get mounts with adjustable MOA cant, and nice ones at that. ERA-TAC has a few mounts that do that well.,,

https://www.eurooptic.com/era-tac-adjustable-inclination-mounts.aspx

Weather or not you really need that is another story. Frank has a post about using Warner Tool bullets in 65CM, and his adjustment at ~1 mile is 8 mils.

I have several of these mounts, and they are WELL made... if a little heavy.

 

[steve123]

Figure out your mechanical center in your scope, total travel divided in half, in that area your optics look the best. Choose the amount of angled base you want based on that and average distance you plan to shoot.

Long story short the 20 should be fine and would enable your scopes internals to be more centered.

Sometimes if the erector is too high or too low the top or bottom of the FOV in the scope will appear offset, in other words it won't look like a full FOV, almost like a moon that's not quite full.

Personally I wouldn't do a 40 moa unless you planned to shoot ELR a lot.

 

[Bkultra]

The other thing to consider is if you are buying a high end mount (Spuhr, ERA-TAC) you may want to use that on another rifle at some point... and Ruger sells a 0moa rail replacement for $39.

 

[Greg Langelius *]

Back around 2005 or so I wrote up an experiment here at SH which I had carried out on the then-new Savage 260 Ghost Dancer SH project rifle.

I had a 20 MOA sloped base installed, and still had about 15MOA of unusable elevation adjustment below the 100yd zero elevation setting. So I began experimenting with .005" brass shims underneath the rear of the base, adding slope MOA's to the setup. When the zero adjustment left about 5 MOA down elevation remaining in the setup. I applied release agent to the contact area on the receiver, and applied bedding compound to the underside of the base, and reassembled the base with the mounting screw snug, but not excessively tight.

Once cured, the shims were removed, the sight mounting was reassembled for a last time, and I now had a custom 30MOA +/- a smidge scope base setup.

By leaving the minimum 5 MOA of downward adjustment, the windage adjustment was spared the binding that occurs as the elevation adjustment hits the end of its travel. The lower range increasingly freed adjustment for additional windage as distances increased, and the 1000yd 28 or so MOA elevation setting now occupied the central range of elevation, allowing maximum windage correction at that more crucial distance. The end result served the purpose admirably, and the cost was minimal.

I was (and remain) a frugal sort, preferring the addition of a little sweat equity into my mechanical solutions, as opposed to throwing money at the problem.

I only replaced that base this past week, with a simple EGW 20MOA base. It's becoming an (in?)convenient fact that shooting at high MOA adjustments is more unlikely in my dotage; although being at 4350ft Altitude, it's become less and less necessary from a practical viewpoint, too.

Greg

 

[stello1001]

You don't need more can't in your base/rings. Your question asks how does one figure out how much can't is needed. Simple, know how far out you will be shooting, find a ballpark figure of how much drop in trajectory, translate that into elevation you'll have to dial, and make then make sure you have that amount of travel left in your scopes reticle after zeroing. For your 100 to 600 yard shots, you could probably even get away with no can't in your rifle. I could be wrong because idk exactly how much elevation travel your scope has, but most high end scopes these days have enough to put a 6.5 projectile at 600 with only the elevation travel in the scope and no can't from the base/rings. With that being said, your 20 moa canted base should be just fine and even allow you to reach out to longer distances once you're ready to shoot past 600 yards! Sorry for the long post, just wanted to make sure I explained everything well enough!

 

[LA260]

I wouldn't worry about getting a 20MOA mount with your setup. You should have about 21mil adj avail. with 20MOA base and 100yd zero which should either get you to a mile or very close to it with dialing.

 

[cuz]

Thanks for the inputs. I went with a 0 MOA Mount for my scope. After zeroing I have 17 mils of adjustment which is more than I’ll ever need at this shooting range.

 

[Primus]

45 moa base or go home