Trijicon for BCM BFH 14.5 Middy

[TacMedic556]

First Build-LE6920, Larue BUIS, with Aimpoint M3 optic on Larue mount. CQB carbine.

Second build in progress now - Recently purchased a BFH BCM Mid-length 14.5 inch. I am considering the Trijicons for this build to serve as primarily a longer distance carbine.

I am considering the TA01NSN, TA11, TA33 or TA31.

I admire the precision as well and built in back up sites on the NSN. I also like the 3.5 power and 3 power of the 11 and 33 for the ability to get less blur should I take shots at closer ranges. I am hoping to buy from Larue, to acquire a Larue mount for the optic and perhaps some dillo dust:p

I have read the chart on here, however the opinions and experiences of others on M4carbine.net always prove reliable and enlightening. Thanks brothers


P.S. Being that the Trijicons drop compensators are calibrated for 5.56 carbines with carbine length gas systems, does the pressure thus velocity and trajectory change by using a Trijicon on a Mid-Length gas system?

[TacMedic556]

Did some research. This helped.

http://www.trijicon.com/na_en/support/faq_ACOG.php

[TacMedic556]

From the Trijicon site itself: The TA01NSN was designed specifically for the US Special Operations Command SOPMOD M4 Carbine. To meet their requirements, the reticle bullet drop compensator and range finding stadia lines were based on the trajectory of the 62 grain bullet from a 14.5 inch barrel, flattop mount (Picatinny rail Mil.Std.1913).

Think the TA01NSN is it for me then.

[TacMedic556]

I am having a great conversation on here by myself. :) ACOG TA31RCO-M4CP seems to be a great option as well. Designed around the Flat Top M4 with a 14.5 inch barrel and the M855 round(62 grain).

This also uses the BAC-Binden Aiming Concept, or "both eyes open" which being a Jeff Cooper admirer I think is a great idea.

Ok then, could this be it? ACOG TA31RCO-M4CP?

[Failure2Stop]

I have extensive time behind the 31, NSN, and 11.
I vastly prefer the 11 over the others.
Eye-relief is a huge issue with the 31 and NSN, and I will never put one on a weapon I carry again unless given no other option.

There seems to be a greater than usual amount of ACOG threads lately. Is there a sale going on somewhere or something?

[decodeddiesel]

The TA33 is an outstanding optic in any trim, and the TA11 is good (but big) where they fall short to a red dot sight is within 50 meters or so. The TA31, TA01-NSN are dated and the crappy eye relief are killers on these optics.

[TacMedic556]

Is the 33 BDC for the M855 62 grain?

[Failure2Stop]

Is the 33 BDC for the M855 62 grain?

Seriously, if you plan to shoot past 300, you will be much happier with something else.

[decodeddiesel]

Seriously, if you plan to shoot past 300, you will be much happier with something else.

I agree. I have the TA33-H and I found that zeroing the dot at 200 yards, then dead holding is the best way to go, however mine is on a 10.5" MK18. Beyond 300 meters you are going to want something with higher magnification.

[TacMedic556]

Yeah, my dad keeps trying to talk me into the Leupold Mark 4 1.5-5x20 in a Larue mount, with an Aimpoint in my gear bag also on a Larue. With that you have good long and good short distance optics. I just wanted one that did ok at both.

For the longest time I wanted the TA11 due to the 3.5 lower power and the larger objective lens. Then I heard great things about the TA01NSN regarding special ops units using them. Then I heard all the great things from guys on here who I trust, talking about the TA33 and TA31RCO-M4CP.

[Failure2Stop]

Look into 1-4X and 1-6x variables.
FWIW- lotsa dudes in tippy-top units and in tippy-top competition use them.

I have significant experience behind the optics being discussed. Low powered variables are where it's at to pull out the performace strengths of an AR. The ones in the same price range as the COGs out perform them at both long and short work. If you don't want to drop the $$ on a good low-powered variable, get an Aimpoint, which at least will do very well at close range for a very long time.

Seriously, if you just want an ACOG, get an ACOG. I constantly advise people against them, but they keep buying them, only to disciver that I was telling the truth.

[shootist~]

It also depends on the specific reticle choice in the various ACOG models. One version I played with briefly on the range had a circle for the zero range with the first hash mark at 400. It pretty much sucked for 8-10" plates in the 200 - 300 meter range. A visible crosshair at 100 with the 1st hash mark at 300 makes more sense if semi-precision work is a goal.

A good low power variable is a better choice IMO, but expect some added weight.

[TriviaMonster]

Look into 1-4X and 1-6x variables.
FWIW- lotsa dudes in tippy-top units and in tippy-top competition use them.

I have significant experience behind the optics being discussed. Low powered variables are where it's at to pull out the performace strengths of an AR. The ones in the same price range as the COGs out perform them at both long and short work. If you don't want to drop the $$ on a good low-powered variable, get an Aimpoint, which at least will do very well at close range for a very long time.

Seriously, if you just want an ACOG, get an ACOG. I constantly advise people against them, but they keep buying them, only to disciver that I was telling the truth.

I too think acogs are past their prime a bit. With so many low power variables out there now, it doesn't make sense to limit yourself.

-Chris-

[TacMedic556]

Thanks for the insight F2S. The more it is discussed the more obvious the choice becomes.

http://www.laruetactical.com/leupold-mark-4-15-5x20mm-mrt-m2-larue-tactical-spr-mount-67905-lt104-30

[Failure2Stop]

Thanks for the insight F2S. The more it is discussed the more obvious the choice becomes.

http://www.laruetactical.com/leupold-mark-4-15-5x20mm-mrt-m2-larue-tactical-spr-mount-67905-lt104-30

I highly prefer something that is as close to 1x as possible and has a mil based reticle (at least) and adjustments.

[lethal dose]

Trijicon tr24 is, in my opinion, the absolute best value in LPVs.

[TacMedic556]

Liking the TA11...still saving cash. Wife has me on a budget, you know.

[5pins]

I have had a TA33 for a little over a year now but if I had to do it all over again I would get something in a 1X4 or similar. I will more than likely keep the TA33 because it does what I need it to do, however if I were to do it all over again I wouldn’t get the ACOG.
As far as TA33 or TA11 question. I have only shot a TA11 once and did not see any advantage over the 33.

[TacMedic556]

I used the TA11 the other day. The eye relief was generous. Acquisition of the reticle (red chevron in this case) was fast, impressively fast. Field of view was great. Clarity also impressive. I like the 3.5x. I was able to acquire targets from 10 yards to 200 yards with ease.

My reason for ACOG as a main choice here is its proven bomb proof reputation and history, battery free, and lack of moving parts. I am a "set it forget it" type. I already have an Aimpoint M3 on my 6920. I want an optic now that can handle engaging targets from 10 yards to 400 yards with more precision (hence magnification). The BDC is also attractive.

My only concern is not knowing how the TA11 will handle on a 14.5 inch Middy. The velocity of the M855 62 grain coming out of the BCM BFH Govt profile is a mystery to me as I do not have access to being able to measure it. I read different things as to which barrel length and 5.56 round Trijicon designed the TA11 around. I read on their sight that:

"The real issue is not the bullet weight or barrel length, but muzzle velocity, ballistic coefficient, and the distance from height above bore. The difference in trajectory from bullet to bullet or barrel to barrel is usually less then the MOA thickness of the stadia lines."

So I am sort of stuck on this point now. I'll keep researching, reading, thinking and deciding. We'll see.

Anyone know what the little black dots refer to (purpose) to the LEFT and RIGHT of the Red Horse shoe are?http://www.trijicon.com/images/product_reticles/TA11H_reticle_popup.jpg

[lifebreath]

I have a similar arrangement, with similar thoughts in mind: 1) QCB setup with Aimpoint, light, UBR stock and Geissele SSA trigger; 2) longer range carbine with ACOG, CTR stock and Geissele SSA-E trigger. However, I went just the opposite of you: 1) QCB is a 14.5" BCM middy with permed A2; 2) longer-range is 16" LE6920 with ACOG. The shorter gun is a little more maneuverable indoors and balances out better with the light and heavy stock. The longer gun seemed better suited for longer outside shooting.

I have two ACOGs, a TA 31 with horseshoe and a TA 11 with illuminated cross-hair. The TA 11 is superior in every way except size and weight, but the eye relief, bright sight picture, FOV and reticle is so much better than the TA31 that I'll accept the size. I'd be interested to try the TA33 as an in-between solution. Also, the TA11 is much easier to use at very close range than the TA31, due to it's eye relief, slightly less magnification and the cross-hair reticle design.

I love ACOGs for a no-fuss, bomb-proof scope. They don't do everything, but what they do, they do well.

My TA11 and TA31 reticles respectively:

http://www.lincolndiagnostics.com/public/doug/guns/TA11-reticle_crop.jpg
http://www.lincolndiagnostics.com/public/doug/guns/TA31H-reticle_crop.jpg

[andy t]

My only concern is not knowing how the TA11 will handle on a 14.5 inch Middy. The velocity of the M855 62 grain coming out of the BCM BFH Govt profile is a mystery to me as I do not have access to being able to measure it. I read different things as to which barrel length and 5.56 round Trijicon designed the TA11 around. I read on their sight that:

"The real issue is not the bullet weight or barrel length, but muzzle velocity, ballistic coefficient, and the distance from height above bore. The difference in trajectory from bullet to bullet or barrel to barrel is usually less then the MOA thickness of the stadia lines."
So I am sort of stuck on this point now. I'll keep researching, reading, thinking and deciding. We'll see.

Remember, that BDC is a best guess, even when using the "right" rifle / ammo, and is also done for a certain temperature and altitude.
The real answer is shooting the gun/ammo combination throughout your engagement distances and figuring where the POI is relative to POA.
What is the furthest distance you are planning on shooting the ACOG equipped rifle? The BDC should be relatively close regardless of ammo / bbl type out to 250-300 yards, assuming you zero the ACOG correctly.