• Manufacturer: Leupold
  • Model: Mark 4 3.5-10x40mm LR/T M2
  • Model Number: 61635
  • Finish: Dark Earth Anodizing
  • Magnification Range: 3.2-9.5
  • Objective: 40mm
  • Tube Diameter: 30mm
  • Eye Relief: 4.7"/119mm - 3.4"/86mm
  • Click Value: .5 MOA
  • FOV: 29.9' @ 3.5x
    11.0' @ 10x
  • Adjustment Range: 65 MOA
  • Reticle: Illuminated TMR
  • Weight: 21.0oz/595g
  • Overall Length: 13.5"/343mm

Leupold is constantly coming out with new models in their Mark 4 tactical lineup, and one of the new models they came out with for 2006 was the 3.5-10x40mm with M2 knobs and earth brown anodized finish from the factory. The M2 knobs are very interesting and I have wanted to take a look at them closely for a while and the only LR scope they are available on happened to come in earth brown, so a few things were worth reviewing.


Leupold Mark 4 scopes have been reviewed by many people, many times, though I just realized I have never done an official write-up on one. I am not sure why, I have several and have used many others over the years. I suspect I’ll have to do another write-up soon on one of the other ones we have here. But, because most everyone is aware of the excellent reputation that Leupold mark 4 scopes have, I will not go into the little details about the scope and optics itself. It is sufficient to say, the optics are OUTSTANDING, the adjustments precise, and the quality top notch. The picture above looking through the scope does not give it justice, and should not be used to show the quality of the glass, it is far superior to that photo. Now that we have that taken care of, we can focus on the other unique things about this particular mark 4 model.


The main feature on this scope that I was very interested in was the M2 knobs and how I liked them vs. the M3 knobs that I very much am a fan of. Both the M3 and M2 knobs are a Bullet Drop Compensating (BDC) knob, set to a specific caliber and load. As you may notice in the above picture, these M2 knobs are closer to the 3.5-10x M3 knobs than the knobs found on the 10×40 M3 scopes (used by the US Army), which are a low profile knob. In fact, these M2 knobs are the same shape and size as the 3.5-10x M3 knobs, so what is the big difference? Well, the ONLY difference is that the M2 knobs are .5 MOA per elevation click while the M3 knobs are a 1 MOA per click. The windage on both the M3 and M2 knobs are the same at .5 MOA per click. The advantage the M2 has over the M3 is that it allows for more precise adjustment and zero (twice as precise… to be exact) The down side is that it now takes twice as many clicks to get to various ranges, which you can get used to, and that you can no longer get to 1000y in a single rotation with the 308. The M2 knobs have 29 MOA of adjustment per revolution and for the .308 168gr Match load that it comes default with, it will get you to 800y in the first revolution, and is marked on the 2nd level for 9 and 10 (1000yards). I think this is an acceptable compromise because the 308 is more practically used from 800 on in, but it is nice to have it indicated out to 1000 in case you need it. Because of that 2nd level on the BDC, care still must be taken if shooting out at 900+ to be sure you keep track of where the BDC is set (300 or 900??). The leupold custom shop will also mark a new knob for whatever caliber you want, so you are not stuck with the .308. Kenton Industries will also make custom marked BDC knobs for this scope, though I do not believe they can do them in earth brown.

The factory says there is 65 MOA of adjustment, though this particular sample had 76 MOA of vertical adjustment, 27 MOA down from factory zero and 49 MOA of up. There should be enough “slop” either direction to zero the scope at 100yards with most typical 308 rifles and still have all the adjustments needed to get to 1000y without a slanted base. You will notice there is a bias in the factory zero to allow for more up MOA. Unless your bases or action are out of whack, you should be okay in most cases. The clicks are precise and offer good tactile feel so you know when the click has happened, and the noise is muted, just the way I like it. I really like these new M2 knobs, I think it is a very good compromise between field adjustments and precision, and I would say I like the M2 knobs as much as the M3’s, though I can’t really say I like them more, both are excellent.

The brown finish on the scope is anodized and very tough. The custom shop has been offering custom anodizing for a few years now, but it is not normally found on a scope in their standard lineup. This particular brown is almost more of a true OD Green/Brown color. It would mix well in either desert or woodland environments. It is a bit hard to explain the exact color. The finish appears to be the same very durable finish as the other black Mark 4 models and should hold up very well.


The reticule on this scope is the Leupold Tactical Milling Reticule, or TMR. The TMR, as you can see in the picture or the reticule higher on this page, has larger hash marks at each 1 Mil interval, and smaller hash marks on the .5 Mil intervals. The idea is to help the sniper get more accurate mil readings. I would say it probably helps some, though I would argue not much, as once a person learns the exact measurements of the traditional mil-dot reticule, one can become just as precise. I do like the 10 mil larger hash marks extended out on the larger stadia, as those can be very useful to add flexibility of your measurements. The TMR reticule is actually opened at the center aiming point, with the idea to not obscure vital portions of the target. It is still reasonably easy to get accurate shot placement, though perhaps not as easy as a fine crosshair. The other very nice thing about this particular scope is that it is illuminated.

mk4brown4  mk4brown5

Leupold’s illuminated reticules are different than most, as when you are looking against a bright target, you will not see the reticule illuminated, even when turned on. You only see it when you are looking against a darker background, and is why the photo above is taken while looking at a dark “blob”. I think this is a very good way of doing it. The only downside is that you may sometimes leave the reticule lit and not realize it, perhaps even storing it with it left on, burning the battery out.

It is apparent that Leupold tried to put together a complete and very capable long range sniping scope, and in my opinion they did a very good job. The knobs are exceptional, and while I do not normally opt for the illuminated reticules on my scopes, they are nice in those few times when you need them. I would probably rather the scope be in black, but either way it is usually wrapped and camouflaged anyway, so its not too much of a concern. The optical and construction quality are excellent and this scope is certainly in the top tier of available scopes for sniping.


michael craig

I’m about to buy a leupold scope for my Parker-Hale 30.06. I don’t understand how to use a scope. After reading the above write-up, I wonder if you have written a scope paper for beginners like me. If not, could you recommend one. Thank you, Mike C.

Mel Ewing

We have a couple of articles in the member area about some of the advance uses, but we do not have a beginners guide. It is a good idea and I’ll see if I can come up with something.


Mel, you mention 7.62 several times in your article. I was planning on buying this scope for my custom AR I built. It’s a 5.56 with an 18 inch barrel and 1:7 twist Wylde chambered. Would this scope be a good match with a 5.56? Even on the turret cap it has 7.62 on it. Sorry for the ignorant question. This is my first AR I built and will be the first good quality scope I use. Thanks.

Mel Ewing

The M2 dials that come on this specific scope have a bullet drop compensator (BDC) specifically setup for the M118LR 7.62 sniping ammo that the US Army uses. So while the scope would work great on your rifle, the BDC itself would not match the 5.56 ammo you would be using. The Leupold custom shop can make you a dial to match your specific load if you wanted.


Do you have an idea on what the custom shop’s cost maybe for such a service. I have a .308


They both are good scopes and should work well. I would look at the feature set of the scopes and go off of what you like. Be aware that the LR/T scopes are no longer being marketed to the civilian market and they have moved on to new models. Mk5, Mk6, Mk8, VX3i, etc. The very sniper dedicated nature of this particular scope with M2 knobs, etc, make me favor it personally, but it may not fit what you need.


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