I am looking for a scope for my new AR build bench gun. My range will be usually 100-300 yards. Might use the gun for Coyote hunting as well. Living here in Florida, you can get some miraging effects from the humidity at the longer distances. My eyes are starting to age so clarity is a great concern for me. One thing I have found that helps me out is side focus adjustments on scopes. I really helps me on longer shots. My Weaver tactical has this feature and I love it. The only problem with the Weaver tactical line for this purpose is the weight of the scope- close to 2 lbs.

The Nikon and Leupold are around 19 oz. and one inch tubes vs 30mm.  30MM just seems a little large for an AR.

The Leupold Mark AR scopes have good reviews for the most part but lack the side focus. To get this option, price goes way up. OTOH, Nikon has this as a feature on the M-223. They have a pretty good sale going on right now and the price for both scopes are pretty close.

Are the Nikon scopes in this price range pretty good. I have searched and found good reviews. However, I would prefer to hear the reviews on this site since this is AR related and lots of people here have the experience and knowledge that I respect.

For a bench gun you might want to step up to the Monarch line to get the magnification you need for small groups. All of the info below applies , just mo better, and mo $.

I have a Nikon Prostaff on my AR 10 (4-12 x 40) with the mildot reticle. I really like it and it works very well for me out to 5-600 yards. Very clear. I am not as fond of adjustable objective lens scopes as I have never really had much need for them. Once I have the ocular adjusted, I am gtg. On the heavier .308 rig I just don't really notice the weight. I would buy another one in a heartbeat.
I also have the P223 with the BDC reticle on am AR 15. It is set up with a 25/300 zero (if I did it right) and I can point and hit just about anything I can clearly see with it. This rifle is a beater/truck gun with little to no sentimental value, so I don't worry much about it. The scope fits very well, glass is very good, it shoots the "square" repeatably, and is a bargain for its price. Again, no AOL, but it's not an issue for me. Hope this helps

What about the bushnell ar 1-4x scope?..

I am looking for a little more magnification than 4x for the longer range shooting. I am hoping that the build I am working on will be capable of some nice small groups using hand loads.

I have the Nikon M223 4 x 16 42mm with BDC reticle (both turrets in 1/4 MOA). the Nikon M223 4 x 16 42mm with Nikoplex reticle has a top turret marked in yards (for use with NATO 5.56 in 55 gr) - even though the clicks are 1/4 MOA. Both have side focus (parallax adjustment). I also have Nikon M223 in 1 x 4 with Point Blank" reticle for off hand shooting - both turrets in MOA. I also have a Weaver T24 with fine cross hairs (fixed power). The problem with 24x is that early summer days, image appears hazy due to moisture in the air.

I have a Nikon M223 3-12x42 BDC and a Leupold Mark ÅR 3-9x40 Mil Dot, both are great rifle scopes.  The glass is clear on both edge to edge.

Pros on the Nikon:  The Nikon Spot On app is on my iPhone and it works great for me, and I like the side focus when shooting off the bench.  I mounted it with a Blackhawk riser and Blackhawk tactical rings.

Pros on the Leupold:  The Leupold is mil mil and I am learning to use the mil dot.  I really prefer this over the BDC.  The turrets are less likely to move in the field compared to the Nikon, and the Nikon's side focus is just one more knob to worry about when you are in the field.  I mounted the Leupold with the Leupold IMS and it looks sharp.  

I would not recommend the Nikon or the Leupold 2 piece mounts.  This creates more error in your mounting system.

The BDC and the mil dot on these two rifle scopes only works on the highest setting.

I have said this before on this forum before and I don't think people agree with me.  Eyes are different, look through each for an extended period of time and one of these scopes will fit your eyes better than the other.  The one that fits me may be different than the one that fits you.

What will the scope be used for most... bench?  or field?  The Leupold is more stream lined and seems less bulky for the field.

However, I would recommend either scope and I have experience with both.

RFutch is a optics guru and he prefers the 3-10x40 Weaver Tactical in this price range.  I have not used this yet so I can't comment.  The Weaver has a different focal plane (1st or 2nd, I get them confused), but you can use the mil dot on various settings.  He has a great review on this scope somewhere.  Maybe he will chime in.

EDIT: I made a error in my statement about the Weaver Grand Slam being a different focal plane.  It has to be on the highest setting as well to use the mil dot correctly.

Between those two you're splitting hairs with glass quality. Neither will be head and shoulders above the other. The Nikons are good scopes but the reticle/turret choices are gimicky.

Vortex makes exactly what you are looking for and quality will be on par with the Leupold and Nikon.

Link.

ETA: In the next price bracket up is the Vortex HST 4-16x44. This is what I would recommend over the others because of the features it offers.

Also what about a fixed power scope? A SWFA SS 12x or 16x would be hard to beat in that price range for a bench gun. They are made in Japan and offer a mil/mil version. Coyotes would be a problem though.

I have the NIkon 4-12 X40 BDC 600 on my AR and I like it a lot. After initial zeroing at 100 yards I am able to score hits on chest sixed targets out to 500-600 yards  with my 55gr hand loads. The Spot On software is just a guide I do not use it religiously. I initially had some issues with the M223 one piece mount causing wind age errors. With some help from this forum I was able encouraged to take a little more care when mounting it to my AR and the addition of a laser bore sighter helped a bunch.

Vince