Do trijicon acogs "ballistic reticles" match our NR black rifles?

[Haakman]

hey folks.
I've been looking at optics options for my NR acr, I've tried the 1-4x's and they were cool but just lacked something, I dunno. too big maybe, or long.

I understand a ballistic reticle is alright for military use, because its going on a standard issue rifle with a specific standard issue round/load that it fires.
But what about the civilian market? how well to the acogs and elcans maintain accuracy along their stadia lines past 200m/yds?

take the acogs for example off the trijicon website "The TA01, TA11, & TA31 (.223) were designed for the 5.56mm, 20 inch barrel, 55 grain bullet, and M16/AR15 carry handle mount."

alright for the .223 reticle its 55 grain .223, but what was it? how fast was it going? etc?
There's so much that can change that will cause inaccuracies the further out you shoot. a big reason why bolt guns pretty much only use mil/moa/mrad etc.

So with my 18.5" bbl NR acr if I get a Trijicon acog say if I were to shoot at a target 400 yards away would I actually be able to use the "4" marked stadia line on the reticle or is the round going to fall somewhere else?

I also have several different kinds of factory .223 ammo and some 5.56, pmc bronze 55gr, some norinco yellow box, some pmc Xtac 62gr M855, that federal white box .223 55gr stuff and so on. if I zero with one kind of round how much is that going to affect me at the longer ranges with this acog? I see theres some info on ar15.com but its all based around the ar platform and 16" barrels and shorter.


so if anyone uses an acog beyond 100 yards with their NR black rifle, can you tell me how well is the accuracy maintained at those longer distances and do you have to use one specific load if not how much variance is there between factory loads in terms of trajectory? like if I buy an acog I want to be able to use it like an acog should, I know its not for precision shooting but if the lines are unusable past 200 yards then no dice. if it stays pretty close, like an moa or so across all the ranges then sure I would buy one.

 

[Ar180shooter]

Depending on barrel length, muzzle velocity and bullet weight, you'll see more than a 1 MOA variance from the BDC reticle. You'll have to do some experimentation to find which loads are close enough for you. In all honesty though, if you're looking at longer range stuff (300-600 yards), I wouldn't suggest going with an ACOG anyways. A variable magnification scope like a Leupold Mark 4 2.5-8 will do much better for you, in both close in shooting and longer range stuff.

 

[TDC]

The ACOG series of optics are designed for shooting people, not winning a precision match. If your goal is to print tiny groups you have the wrong optic for the job.

TDC

 

[celtic1123]

OP it might help if you tell us exactly what you plan to be shooting at (paper, yotes, etc.). As was stated ACOG is meant to hit a man sized target at those ranges not print competition groupings.

 

[Haakman]

Not paper shooting. Ringing gongs and coyotes, typical NR black rifle fun stuff. Not looking for precision I'd get another US optic scope for it if I was, more or less kinda looking at similer performance as military rifles which is why I considered the acog, but if the changes in barrel length and not having the specific load that the acog reticle is calibrated to means not being able hit say a 12" gong at 400 then it's not really useful to me. (Using the "4" stadia line at 400 should develops a hit, but if the changes between everything mentioned means it's low or high, that's not useful)

Hope that helps.

 

[fuzzynuts54]

You'll never be able to get around changing velocitys amoungst different manufacturers. That bein said you could always zero your acog at 400y on the 400y stadia and all ranges inside of that will match the corresponding stadia quite well.

I just screwed around with my ballistic app that has served me very very well, I trust it's predictions.
Choosing m193 @ 3250fps, zeroed at 400y it predicts 6.9 high@100, 11 high@200, 9.4 high@300, 0@400
Adjusting the velocity down to 3100fps predicts......... 7.8.................12.4..............10.6 .............0@400
Adjusting down to 3000fps..…..................................8.5.................13.5..............11.5...............0@400

I'd say whatever ammo you shoot will match the stadia close enough provided you zero it at longer ranges.

 

[Long]

The ACOG TA31 5.56mm BDC reticle is designed around a 20'' barrel firing M193 5.56mm ammunition.
Performance stats to calculate the BDC with M193 ammo are as follows:
M193 traveling at 3,259fps with a BC of .243 and a height over bore of 3.5"

Given that you would be using an 18.5'' barrel flattop the BDC should be pretty much dead on out to around 600m if you are running ammo that roughly matches M193 performance.

If you ran ammo that more closely matched M855 performance (2,970fps with a BC of .304 and a height over bore of 2.5" ) you would need to Sight in 0.8" high at 100 (or sight in at 60). You'll be 0.5" high at 200 and then dead on the BDC to 500 where you'll be 3" high and 600 you'll be 8.5" high.

I run a 14.5'' barrel with a TA31F reticle (calibrated for M855). With M193 ammo it's a half inch low at 300, 3" low at 400, 9" low at 500 and 15" low by 550. The 55gr loses gas fast past 300, so there isn't much you can do here without making your near zero absurdly high.

For most 3 gun stuff the TA31F BDC works fine with M193. If I want to use the BDC past 400m I just zero it with 62gr ammo matching the M855 round and then I am good to go.