Leupold Mark AR Scope - How do I use this thing?

[Lovesbeer99]

I got the Mark AR and so far I like it but there are no instructions for how to use the drop/elevation. I phoned Leupold and they apologized for not having any instructions. So I zeroed the rifle on 100 yards. Now what?

Thanks in advance.

 

[TonyAngel]

Are you talking about the model with the mildot reticle and the knobs that are supposed to be marked so that you can dial for distance?

If so, do some research and learn how to use a mildot reticle to determine distance. Once you have your distance determined, use the knob to dial for that distance. If you know your distance, then all you have to do is dial.

....If my memory serves me. Sorry, I mess with a lot of scopes and can't remember then all, all of the time.

 

[ugaarguy]

Assuming this one has the yardage marks on the turret...

Going from memory when I sold these, but this should help.

Now that you're zeroed at 100 yards, you're ready to do the other step. There should be an Allen wrench / hex key in the box with the scope. If not, use one you already have (or buy one) to loosen the elevation knob turret. Once loosened, the turret will lift up, and move freely without adjusting the elevation knob underneath. Move the turret so that the zero hash on it matches the zero hash on the scope body. If you're looking the through the scope, when you look through the scope from the firing position the zero hash should be facing straight at you. Take the Allen wrench / hex key, and lock the turret back onto the adjustment knob. Now when you turn the elevation turret to the desired yardage marked on the turret the scope will adjust to roughly that yardage (the calibration is for M193 ball from a 20" bbl IIRC).

 

[BruceB]

The turret is marked with the load for which it's calibrated. Mine says ".223 Rremington 55 gr 3100fps".

It just so happens that my personal load for this rifle IS a 55 V-max at 3097 fps average. When the rifle is zeroed at 200 yards and the turret set to READ 200 yards, I find that adjusting the turret to read,say, 400 yards DOES give me a usable trajectory for good hits at that 400-yard distance. In other words, the system works.

Leupold will supply turrets calibrated for other loads on receipt of the load's particulars.

I have two Mark ARs, and both are functioning perfectly. The 1-4X version does not have the trajectory-compensation feature, but it's still an excellent sight.

 

[lencac]

Some data is needed. A person needs to know the bullet weight and that bullet's ballistic coefficeint and the velocity of a particular load. Decent chronies can be bought for about $150. Then a ballistics program needs to be employed to calculate the trajectory for various distances.
Now with the rifle/scope combination set up at 100 yrds. the shooter needs to place the reticle on a target with known 1 inch graduations. The shooter can then visually look through the scope and determine the spacing of the mil-dots. Most real mil-dot scopes have a 3.5 in. spacing between mil-dots. But different scopes may vary so check this on your particular scope. The shooter will need also to measure the distance between the centerline of the scope and the centerline of the barrel. That distance will be somewhere in the 1.5 in. to say 2.50 in. range
Now having done all that here's the deal.
Example: With the rifle zero'd at 100 yrds. and a distance between the scope centerline and the barrel centerline of 1.750 in. and a .308 dia. bullet @ 2800 fps and a BC of .500 the shooter will need the point of impact to be 14 in. high @ 100 yrds. to hit a target at 600 yrds. If your scope has 3.5 in. mil-dot spacing then you would need to hold the 4th mil-dot below the center crosshair on the target at 100 yrds. to get the POI to be 14 in. high @ 100 yrds. With that accomplished you now know that to hit the target at 600 yrds. all you need to do is place the 4th mil-dot down on the target at 600 yrds to hit that target. It's really quite simple. This same load to hit at say 800 yrds. needs to be 22.60 in. high at 100 yrds. and so on and so forth. This process works for any type of range finding scope. The key is having knowledge of your equipment, bullet flight characteristics and ballistic tables. Without that knowledge you are just spitting into the wind. Make all your calculations in terms of how much elevation is needed at 100 yrds. to hit at any given distance.
It's not rocket science ................ but not too far from it

 

[BruceB]

I disagree that it's as complicated as all that.

The velocity as "predicted" by a loading handbook should be close enough...a hundred feet per second or so of variation would be largely meaningless for this purpose. A personal chronograph is certainly useful, but not required. I HAVE chrono'ed my standard load , which runs very close to the scope's calibration figure (3097 fps average vs 3100 fps on the turret).

If Leupold is given the velocity and the bullet weight/type, THEY can compute the turret dimensions needed for a "custom" turret. I'd wager that the vast majority of our .223 rifles are used with something close to a 55-grain bullet at 3100, though....which is why that turret is supplied as the "basic" setup in the Mark AR scope.

Mil-dots do not enter this equation....they're useful for range estimation, but that's a different topic from range SETTINGS. A low-cost rangefinder will suffice for "average" shooters at longer ranges....we're not speaking here of snipers or match shooters.

With MY Armalite AR-15 rifle, a properly-adjusted Mark AR 3-9x range-adjusting scope, and a factory-supplied turret marked as I said, my rounds impact pretty-much on point-of-aim on a full-size steel IPSC silhouette at 400 yards, with a 400-yard sight setting....meaning RELIABLE hits on a man-size target at 400 yards without hold-over.

No rifle measurements are required. Zero the rifle and its load for point-of-aim impacts at, say, 200 yards. Adjust the turret to read "2" at that setting, and lock it. If your ammunition is close to that marked on the turret, you are DONE. It's not terribly refined, but neither are most shooters OR THEIR REQUIREMENTS.

These results are all I want or expect, and it makes my rifle/scope combo a highly-effective system out to that 400-yard range and probably even further. I have not tried it at any greater distance to date, but I will when the opportunity arises. 500 yards is a LONG push for a .223 bullet under field conditions!

 

[lencac]

I disagree that it's as complicated as all that.

Of course you would disagree. Why would I expect anything different.
However after reading your reply it appears we are in total agreement. Even though you may not realize it.
The method I layed out works for any rifle with any type of range finding scope.
With accurate information about ammo and equipment this method WILL result in a hit everytime at any distance as long as the shooter does his part

 

[BruceB]

Do we have some history, of which I'm not aware?

"Of course you disagree. Why would I expect anything different?"

That seems (to me, at least) to be a personal, confrontational reply. If it wasn't intended that way, my apologies...it's difficult to fully comprehend what meanings are to be attached to words, sometimes.

However, you posted a very complex reply to a very simple question: "How do I use this thing?" I agree completely that the method you detailed will work.

Leupold has greatly-simplified the process for the average scope buyer/user with the introduction of the Mark AR, which is a RANGE-COMPENSATING instrument.

I understand and use the mil-dot system, and am familiar with calipers, micrometers, and chronographs. None of these are needed for mounting or using the Mark AR, although a chronograph surely is useful.

 

[TonyAngel]

Although I'm not a big fan of Leupold, it seems to me that they did many a favor by offering a mildot reticle to be used for ranging and took the math out by putting the dial ups for specific ranges directly onto the turrets. No more converting mils to MOA.

 

[ugaarguy]

LB99, If you want to learn how to use the Mil Dots to calculate range, windage, and elevation here's a good primer - http://www.mil-dot.com/user-guide .

ETA: If you have a smartphone (Android OS, Apple iOS, etc) there are several good ballistic calculator apps (both free & paid) that will do the math for you when you enter a few variables manually.