Never used an ACOG before, and this is my first AR. (AR-10) No scope on it yet, and I'd like to pick y'alls brains first for advice...

From all I've read, most conventional scopes (Leupold, Nightforce, etc.) won't go 1000yd on an AR-10 without an inclined base. Can the TA11E / TA02NSN be used on an incline base with some adjustments, or should these scopes be regulated to < 800yd and left to flat bases?

In any case, what base do y'all suggest for an ACOG, if I wanted to set it up as a detachable scope to go to 1000yd (is that even possible)?

Thank you.

Your comparing apples to oranges.

First the eye relief of a TAo1 series scope is too short for an AR10 so its out right off the bat.

Now you are trying to shoot 1000 yards with a 3.5X fixed magnification scope?  I dont mean to be rude but that smacks of someone who has NEVER shot at 300 much less 1000 yards in real life.  In THEORY you can shoot a 3.5X scope at 1000 yards but in REALITY you just cant see a prone man at all with 3.5X scope.  Now I will admit a 3.5X scope can be used at 300 yards+.  I have done that myself.  However when you are speaking of tapered bases you are comparing two entirely different kinds of scopes.

You see the conventional scopes Leupold, Nightforce etc are adjusted with the elevation knob.  You turn the elevation knob to get the reticle to be on target at whatever range.  Certain scopes dont have enough adjustment to be on target past 800 yards.  The tapered bases for bolt guns solve this by getting the scopes to have to adjust into the very top of their adjustment area to allow for more elevation adjustment at longer ranges.  This is more common in 1 inch scope tubes where there is less romm for adjustment and less common in 30mm tubes.

Now the TA11 is totally different.  The BDC markings are etched inside the scopes view.  You simply hold over at the designated crossbar.  Since the scope is not adjusted using the elevation knob but the reticle itself you dont have the issue of running out of room and thus no need for the tapered base in that kind of scope.  In fact there are no tapered bases for conventional scopes for the AR platform I am aware of, only bolt guns.

You will also run into yet ANOTHER problem.  You see with the short 20" barrel of an AR10 you lose a few precious FPS.  Your bullets will be approaching the speed of sound out to 800+ and accuracy degrades significantly for 20" barrels shooting .308 at that range as the bullets approach trans sonic speed and they destabilise slightly.  While a 168 grain bullet is almost at the same speed as a 24" barrel the 175 (which holds its velocity better at long range) is moving a lot slower from a 20" barrel.  So no matter what your almost assured of accuracy problems at over 800 yards with an AR10 because of the barrel length.

While its nice to want your rifle IN THEORY to shoot sub .25 MOA and to be able to make hits at 1000 yards the reality is just not there.  An AR10 is an excellent 600 yard rifle.  800 is pushing it.  If you still want a quick detatch scope like a Leupold 3.5-10 make sure you get a 30mm tube and use the ARMS 35 QD mount.  It does not have a tapered base but it will allow you to shoot as far as your rifle and abilities will allow.  Once you put up a sub 12" group at 800 yards come back and we can discuss how to stretch you out to 1000. [;)]

Trijicon has a new product?  What's TA02NSN? [:p]

Thanks very much for the detail, DevL. I've done some shooting at the 1000yd line, but of course that's with a 24" Rem 700 and a Nightforce on a 20" inclined base. I use 175 SMK's for that, and sometimes play with the 178 AMAX's also.

The AR will have a 24" Rock barrel, but I haven't decided on the base. GGG offers a 20-degree base; Larue Tech offers a one-piece ring/adaptor for conventional scopes also (I'm not sure if they offer separate bases though). I've got a 30mm tubed Nightforce that'd work with either of these bases, but I was wondering what options are possible if I were to use an ACOG for "short" range.

You make a good point about 3.5x at 1000yd, but I was more thinking about the BDC subtended reticles (TA11E)in relation to this posting. Still, 3.5x for these old eyes would be tough; I was just musing to see if it'd be possible to ACOG the rifle in a pinch at 1000yd.

Well then if you have found a tapered base for a flat top AR there are the ARMS QD rings.  The 24" barrel will certainly get you to 1000.  I would not be so ready to jump into QD rings though as they are never as stable for ultimate accuracy as rings that are meant to stay on the rifle.  everything with an ARMS mount can shift slightly if impacted.  Its the nature of the QD design.  This normally would not matter but if your looking for a 1000 yard shooter I would not leave that to chance.

Why did you want a QD optic anyway?  A 24" match barrel is not something you usually use for a combat-esque type of role unless its a dedicated precision weapon.  Are you wanting to swap out another optic or NV scope or something?

I have another .308 (unscoped, no irons) that seldom gets fired, and I've just been turning the idea over in my head of moving the one scope between the two guns. I'm so unsure of what direction to go in (scope-wise), that I'm just trying to seek advice on what's possible/practical from more experienced folks.

Thanks very much.