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12/11/2018 1:58:31 AM
Posted: 12/2/2018 3:19:11 PM EST
[Last Edit: 12/2/2018 3:21:07 PM EST by Hojo15]
I have this ACOG and not sure if it belongs on a 14.5-16" or a 20" barrel firearm. In the black area at the bottom of the reticle it has TA31RCO-M4 which leads me to believe it is for the shorter barrel. Can someone help a brother out. This was given to me by a returning soldier about 8 years ago.



Link Posted: 12/2/2018 3:51:15 PM EST
M150 is a blended reticle ment to be close enough for either the carbine or rifle.
Link Posted: 12/2/2018 3:51:58 PM EST
[Last Edit: 12/3/2018 6:58:14 AM EST by Styer]
Yep, RCO-M4 was calibrated for M855 through a 14.5 M4 barrel
Link Posted: 12/2/2018 4:19:39 PM EST
[Last Edit: 12/2/2018 4:21:17 PM EST by BarrettBoy]
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Originally Posted By Styer:
Yep, RCO-M4 was calibrated for M855 through a 14.5 M4 barrel
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This.

But don't worry too much about cartridge specs and length.
It's all relatively approximate.
If it really bothers you, just change the zero.

Congrats on the scope.
It looks pristine for a bringback.
FYI Trijicon will still service it for you even though it's mil. Obviously without warranty though.
Link Posted: 12/2/2018 5:15:08 PM EST
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Originally Posted By Postal0311:
M150 is a blended reticle ment to be close enough for either the carbine or rifle.
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This. Yours is an M150.
Link Posted: 12/2/2018 5:52:30 PM EST
[Last Edit: 12/2/2018 5:53:32 PM EST by doty_soty]
Don’t overthink it. Put it on whatever .223ish gun you want and rock on, it’s not really going to matter.
Link Posted: 12/2/2018 8:59:13 PM EST
[Last Edit: 12/2/2018 9:01:25 PM EST by Hojo15]
Thanks everyone for the information, it's currently on a 16" mid length but I have a couple of 20" rifles that I was thinking of making an A4 clone and I think this might work for that. I didn't show the other side but it is one with the bible verse ground off and covered with epoxy.

Was the 150 marking have anything to do with what branch used it, say Army or Marines?
Link Posted: 12/2/2018 9:02:31 PM EST
The M150 model was built to the Army spec.
Link Posted: 12/2/2018 9:51:12 PM EST
[Last Edit: 12/2/2018 9:52:12 PM EST by AL25]
I literally just finished mounting a TA31 on a Colt A4 earlier today. I never liked the TA31 because of the eye relief, but always liked the look of the USMC rifles. I decided to build one and for whatever reason it seems like the eye relief isn't as bad on the rifle. I can't wait to get out and give it a try. I have the TA91 ARD, but it's a lot shorter than the one on your ARD. Do you know what model yours is?
Link Posted: 12/2/2018 10:05:45 PM EST
He has the laser filter.
Link Posted: 12/3/2018 1:38:42 AM EST
[Last Edit: 12/3/2018 1:44:39 AM EST by Locutus494]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Styer:
Yep, RCO-M4 was calibrated for M855 through a 14.5 M4 barrel

ETA: looks like yours is actually a M150 so go with above answer.
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Originally Posted By Styer:
Yep, RCO-M4 was calibrated for M855 through a 14.5 M4 barrel

ETA: looks like yours is actually a M150 so go with above answer.
Originally Posted By 0100010:

This. Yours is an M150.
No, I don't think that's the case. His is a TA31RCO-M150, however it says TA31RCO-M4 inside the reticle, which suggests it has been refurbished and the -M150 reticle replaced with the -M4 reticle. If so, his is calibrated for M855 from a 14.5" 1/7 twist barrel.
Link Posted: 12/3/2018 1:43:15 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Hojo15:
Thanks everyone for the information, it's currently on a 16" mid length but I have a couple of 20" rifles that I was thinking of making an A4 clone and I think this might work for that. I didn't show the other side but it is one with the bible verse ground off and covered with epoxy.

Was the 150 marking have anything to do with what branch used it, say Army or Marines?
View Quote
Yes, the TA31RCO-M150CP is the Army model; the scope is the same, the only real difference is the accessories it comes with. The -M150 has objective and ocular lens covers. The TA31RCO-A4CP is the USMC standard issue (or was anyway) for the M16A4, and the TA31RCO-M4CP is the USMC standard issue for the M4. The USMC models do not have lens covers.

You say yours has the bible verse ground off? Sounds like it was military property. Hope it got sold legitimately...
Link Posted: 12/3/2018 5:56:43 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Locutus494:
Yes, the TA31RCO-M150CP is the Army model; the scope is the same, the only real difference is the accessories it comes with. The -M150 has objective and ocular lens covers. The TA31RCO-A4CP is the USMC standard issue (or was anyway) for the M16A4, and the TA31RCO-M4CP is the USMC standard issue for the M4. The USMC models do not have lens covers.

You say yours has the bible verse ground off? Sounds like it was military property. Hope it got sold legitimately...
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Originally Posted By Locutus494:
Originally Posted By Hojo15:
Thanks everyone for the information, it's currently on a 16" mid length but I have a couple of 20" rifles that I was thinking of making an A4 clone and I think this might work for that. I didn't show the other side but it is one with the bible verse ground off and covered with epoxy.

Was the 150 marking have anything to do with what branch used it, say Army or Marines?
Yes, the TA31RCO-M150CP is the Army model; the scope is the same, the only real difference is the accessories it comes with. The -M150 has objective and ocular lens covers. The TA31RCO-A4CP is the USMC standard issue (or was anyway) for the M16A4, and the TA31RCO-M4CP is the USMC standard issue for the M4. The USMC models do not have lens covers.

You say yours has the bible verse ground off? Sounds like it was military property. Hope it got sold legitimately...
Didn’t they start grinding it off on all of them? I assumed they switched it on all 31’s just for the sake of simplicity.
Link Posted: 12/3/2018 9:56:15 PM EST
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Originally Posted By doty_soty:

Didn’t they start grinding it off on all of them? I assumed they switched it on all 31’s just for the sake of simplicity.
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You might be right; I seem to recall some kerfuflle put up by some self-absorbed PC trash outfit over that years back. "OMG a bible verse!"
Link Posted: 12/5/2018 12:10:49 AM EST
[Last Edit: 12/5/2018 12:11:10 AM EST by Locutus494]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By doty_soty:

Didn’t they start grinding it off on all of them? I assumed they switched it on all 31’s just for the sake of simplicity.
View Quote
No. The grounding off of the bible verse was their "fix" that they gave to the military. There would be no need for a commercially sold ACOG to be sent back to Trijicon. They changed the manufacture of their ACOGs since that (bullshit) controversy surfaced. The forging on the right side now only reads "ACOG4x32"; so they've made a new mold without the bible verse. The bible verse has now been moved to the left side as part of the laser engraved markings there; it's in the last line of text on that side. This allows them to still include the bible verse on their commercially sold ACOGs while omitting it from the ones they sell to the military, but not require two separate molds for the housing. Below are some pics of my commercial TA31RCO-M4CP showing how they moved the bible verse:

Link Posted: 12/5/2018 12:35:29 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Locutus494:
No. The grounding off of the bible verse was their "fix" that they gave to the military. There would be no need for a commercially sold ACOG to be sent back to Trijicon. They changed the manufacture of their ACOGs since that (bullshit) controversy surfaced. The forging on the right side now only reads "ACOG4x32"; so they've made a new mold without the bible verse. The bible verse has now been moved to the left side as part of the laser engraved markings there; it's in the last line of text on that side. This allows them to still include the bible verse on their commercially sold ACOGs while omitting it from the ones they sell to the military, but not require two separate molds for the housing. Below are some pics of my commercial TA31RCO-M4CP showing how they moved the bible verse:
https://drive.google.com/uc?export=download&id=1ynHzcKfxKjVfaluT8HKDSIKlD0RB-7mD
https://drive.google.com/uc?export=download&id=1L3EpLTlY_z7X7zMD-dt7Iww0-41MT_uY
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Originally Posted By Locutus494:
Originally Posted By doty_soty:

Didn’t they start grinding it off on all of them? I assumed they switched it on all 31’s just for the sake of simplicity.
No. The grounding off of the bible verse was their "fix" that they gave to the military. There would be no need for a commercially sold ACOG to be sent back to Trijicon. They changed the manufacture of their ACOGs since that (bullshit) controversy surfaced. The forging on the right side now only reads "ACOG4x32"; so they've made a new mold without the bible verse. The bible verse has now been moved to the left side as part of the laser engraved markings there; it's in the last line of text on that side. This allows them to still include the bible verse on their commercially sold ACOGs while omitting it from the ones they sell to the military, but not require two separate molds for the housing. Below are some pics of my commercial TA31RCO-M4CP showing how they moved the bible verse:
https://drive.google.com/uc?export=download&id=1ynHzcKfxKjVfaluT8HKDSIKlD0RB-7mD
https://drive.google.com/uc?export=download&id=1L3EpLTlY_z7X7zMD-dt7Iww0-41MT_uY
Ah that makes sense thanks for that. I assumed making changing the mold would be the issue.
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