ACOG Ballistic Reticle

[Singlestack Wonder]

Is the ballistic reticle on the Trijicon TA31F calibrated for a 16" or 20" barrel? On the Trijicon website, some ACOG models specify barrel length while most do not.

[PPGMD]

Don't quote me on this, but I am pretty sure that the Marine RCO is calibrated for the M855 out of a 20" barrel for the M16 labeled one, and 14.5" barrel for the M4 labeled one. The Army one is calibrated for the same ammo, but is only offered for the 14.5" barrel.

It's been a while since I talked to Trijicon about it, so I may be remembering it incorrectly.

[ICANHITHIMMAN]

I had one on my 20" rifle it shot right on out to 800 meters I tryed it on my 16" bbl upper and It was only on out to 300 meters beyond that was anyones guess. U need the TA31RCOM4 or the TA01NSN

[Singlestack Wonder]

I had one on my 20" rifle it shot right on out to 800 meters I tryed it on my 16" bbl upper and It was only on out to 300 meters beyond that was anyones guess. U need the TA31RCOM4 or the TA01NSN

Trijicon's states that the TA31RCOM4 is for a 14.5" barrel and gives no specification for the TA01NSN.

Since barrel length is important in regards to calibration of scope reticles, I'm surprised that Trijicon does not post the barrel length calibration for all of the ACOG's.

[Iraqgunz]

I am fairly certain tha the NSN model is for 20 in. barrels. I am also fairly sure that if you email them they will answer. I have been in contact with them before and they usually answer within a few days.

Trijicon's states that the TA31RCOM4 is for a 14.5" barrel and gives no specification for the TA01NSN.

Since barrel length is important in regards to calibration of scope reticles, I'm surprised that Trijicon does not post the barrel length calibration for all of the ACOG's.

[Iraqgunz]

I just went through my email from Trijicon. I was told that the TA31F would work fine on my 16.1 Recon upper. The sight was designed and calibrated with M855 ammo. When I inquired about using it with 55gr. ammo they said that out to 300M the sight should work with little noticeable difference.

Is the ballistic reticle on the Trijicon TA31F calibrated for a 16" or 20" barrel? On the Trijicon website, some ACOG models specify barrel length while most do not.

[MisterWilson]

I am fairly certain tha the NSN model is for 20 in. barrels. I am also fairly sure that if you email them they will answer. I have been in contact with them before and they usually answer within a few days.

Actually, the TA01 is for 20" barrels while the TA01 NSN is for 14.5", that much I'm sure of.

As for which ammo it's calibrated for, I believe that the TA01 is for 55gr 5.56 while I'm not sure about the TA01 NSN...855?

I know this because I mistakenly sold someone a TA01 thinking that it was the NSN model.

[Iraqgunz]

This is the response from Trijicon.

William,

Thank you for your interest in Trijicon products. I recommend you consider our model # TA31F for your AR which was calibrated based on M855 ammunition.

Sincerely,
Eric Lockhart
Customer Service
1-800-338-0563
ext 148

[Singlestack Wonder]

Found this information on the Trijicon site under "FAQ""

» 03. What bullet was used to calibrate the ACOG scopes?
The TA01, TA11, & TA31 (.223) were designed for the 5.56mm, 20 inch barrel, 55 grain bullet, and M16/AR15 carry handle mount. The TA01B & TA11C(.308) were designed for the 7.62mm, 20 inch barrel, 168 grain bullet, and M16/AR15 carry handle mount. 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).