20 MoA rings for AR or not?

[Saggins]

I recentry bought an AR-15 in 223/5.56 with a 20" 1:7 barrel to use for mostly midrange (out to 600yds) and maaaaaybe a little 1000yd shooting at home. The primary user is my son (he wanted an AR over my recommendation of a bolt-gun, but I didn't argue too much about it, it was a good price). I happened to see a Cabelas Covenant 6-24×50mm FFP in the bargain cave for $130 ($299 normally) so I grabbed it for this project. Hard to pass on it for the price.

Anyway, according to the website it has 40 MoA of adjustment. Which leaves me 20 MoA up or down. From what I get from JBM ballistics, my loadings should shoot 600yds anywhere from 16 MoA to 19 MoA. Which initially seemed perfect for a set of 20 MoA rings to me, until I remember there's only 20 MoA each way... when zeroed at 100 (or maybe 200yds) for more practical shooting I will be close to maxed out (the sight offset helps save me about 2 MoA) the oposite way with almost 38 MoA of adjustment left for drop. The alternative is using standard rings and hold over. The reticle does have convenient windage markings and at least 36 MoA of drop marked. So is a set of 20 MoA rings worth it or just use hold over? A different scope with more adjustment would make a big difference, but it does have a lot of features we like a lot for a great price.

(Sorry if it's a ramble, not always easy for me to put this stuff into words haha)

 

[LoonWulf]

If your using it primarily at 300-600yds id definitely go with a 20moa canted mount.

I use hold over a lot, as i dont spin turrets, and my guns are mostly sighted for mpbr. What i do, would be better termed as mid range "plinking". I also dont shoot "long" range, nothing outside of 400-450yds (edge of my range finders effectiveness on the rocks and things I plink at) and expect a first round hit, I walk shots onto target.

The issues ive found with hold over is its easy to cant the rifle, and adjusting for wind can be trickier. If your using dialed range drop compensation, you can use your horizontal crosshairs for windage compensation. Using hold over its more difficult to adjust for wind.

 

[ms6852]

I have a BDC reticle on my scope that is calibrated to 75 grain bullets. According to this I am supposed to go to only 500 yards but I have zeroed it at 200 yards and now I use the bdc to 600 yards without having to dial up on the elevation knob. I figure if you have a bdc scope and zero at 300 you have enough for 700 yards leaving enough elevation to dial in without using a 20 moa. I have also zeroed at 100 yards and the BDC works to 500 yards. I believe that the bullet drop compensators are calibrated according to your zero.

 

[Saggins]

This should help, pictute of the reticle. This one isn't a BDC, but is true MoA at all zoom levels (first focal plane).

 

[Saggins]

I guess to sum it up it, with that scope, it comes down to either would you rather be 1: in the center of adjustment range at your zero (100-200) and almost at the end of adjustment at 600 or just using windage (this would be with standard rings) or 2: being almost and the end of adjustment at zero (100-200) while being in the center at 600 with some room to go beyond (this would be 20 MoA rings)?

 

[cdb1]

For your stated purpose Saggins I’d go with 20 MOA rings.

 

[Varminterror]

I use 20MOA mounts, bases, or rings on most of my rifles and handguns, but there are plenty of optics out there which will let a guy go long without angled bases. I prefer to have access to as much of my adjustment as possible.

 

[z7]

Does the scope have exposed turrets for easy dialing?

If so, I think a 20 moa set of rings, or maybe better 15 moa rings could help, my concern with a 20moa base with only 40 moa of adjustabment May mean that your zero is at the limits of the turrets, this also reduces available windage adjustment

Holdovers with that reticle are quick and easy for decent sized targets and plinking, but I bet it will get a little distorted/dark at the bottom/edges

 

[Saggins]

my concern with a 20moa base with only 40 moa of adjustabment May mean that your zero is at the limits of the turrets

This was my main concern as well, but the bore offset buys me a little room. Theoretically if the installation was perfectly lined up with the bore and scope offset was 2" with 20MoA rings. My initial 100 bore sight SHOULD be 18 MoA high... leaving me 2 MoA... but again...how often do things work out perfectly? And a 200yd zero should give me even more room, right?

 

[Saggins]

I may have found another option... using Burris XTR Signature rings, and adjusting them for a custom amount of correction (15ish give or take). But therein lies another problem, can I get proper eye relief without a cantilever mount?

 

[z7]

This was my main concern as well, but the bore offset buys me a little room. Theoretically if the installation was perfectly lined up with the bore and scope offset was 2" with 20MoA rings. My initial 100 bore sight SHOULD be 18 MoA high... leaving me 2 MoA... but again...how often do things work out perfectly? And a 200yd zero should give me even more room, right?

Yeah when I switch my qd mount between 3 at platforms I have about 5 moa of vertical and 3 moa of windage to adjust between the rifles

 

[Klint Beastwood]

For an AR I’d try a 20 moa riser first. It really will depend where your zero ends up how many mils or moa you’ll have left. I usually only get about 12 to maybe 13 mils total...but that’s been plenty combined with the right BC and muzzle velocity for 1000y. Still, hope you got a good spotting scope, hard to see splash or hear impacts at that distance, at least for me with the ELD match out of a suppressed 18 inch tube.