Trijicon ACOG...

[JDavis1776]

I have two m4gery's. One has a 1 in 7 twist. The other has a 1 in 9 twist. I built the second on for the 1 in 7 twist to utilize the heavier loads with a 3x9 scope. The scope has BDC to 600 for a variety of .223 loads. Now, the acog I have has BDC for 62 gr M855. If I were to use the acog on the 1 in 9 twist for shots to 300 yards. What kind of accuracy should I expect from the acog utilizing the traditional 55 gr ammo. I would like any suggestions on the issue. Really I just want to now which rifle I should have which scope on.

I currently have the acog on the 1 in 7 twist build, and the 3x9 scope on the 1 in 9 twist.

[MistWolf]

Have you shot them yet? 55 gr will work with either twist but you won't know what the best combo will be until you go out and shoot them

[JDavis1776]

yes I have shot both of them. I have XM193 and M855. I know the BDC on the Acog is exact for the M855, but if I use the other scope on the 1 in 7 twist with the M855 I can get better range out of it. I really need to know about how accurate the Acog will be with the 55 gr stuff out to 300> I know the trajectory really won't be too far off if I were to use the 55 gr with the Acog. I just want to be able to maximize my range with the 62 gr M855 on the 1 in 7 twist rifle

[MistWolf]

In general, because of the higher magnification and finer reticle, the 3x9 will give the shooter greater precision at longer ranges than the ACOG, assuming the 3x9 is a scope of good quality.

Find which carbine & ammo combination will give you the best precision at the intended ranges and mount the 3x9 on that one. Perform your tests using the 3x9.

To find out how accurate the ACOG will be out to 300 with the 55gr ammo, you'll need to shoot that combination out to 300. Make notes. BDC has marks, but they are suggestions not absolutes

[Frens]

I've tried my TA01NSN on my Colt6731 (1/9) with .223 55gr at 200m

I'm not a sniper and was my first time at 200m... made a 15cm group...the BDC worked just fine even with the wrong twist, ammo and bullet.
I think the BDC would be way off from 400m..

as already said BDC marks suggestions not absolutes (even with the right twist,ammo, bullet) and made to hit a human torso not to make groups ;)

[JDavis1776]

Thanks. I don't intend on shooting over 300 with the Acog. It is the TA31RCO-M150CP. So I'm assuming it will be accurate enough for hogs out to 300.

I had the 1 in 7 with the 3x9 to begin with, but then someone told me I should switch them. So, now I'll just have to switch them back and re-zero both of them.

[TehLlama]

You'll be plenty accurate for hogs with that setup if you do you part. I think the biggest BDC induced error you could create (using 40gr rounds) at 300m will still keep your POI on target.