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Posted: 8/30/2026 11:06:36 PM EDT
| Hey all, I’ve got a TA31F that may get pushed into use on a 20” 5.56 rifle. Anyone know how well the BDC will still line up? I think the F is calibrated for 62gr from a 16” flat top rifle. |
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I ran that model on a 20 and with M855 the BDC lined up perfectly. I zeroed using the 300 meter post at 36 yards and elevation was perfect out to 500. I never got around to testing it at 600. I did true the 36y zero at 300 meters, which was windage only. I sorta wish I hadn’t traded the Cog for the Razor. |
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Originally Posted By Coordinate_Cowboy: Hey all, I’ve got a TA31F that may get pushed into use on a 20” 5.56 rifle. Anyone know how well the BDC will still line up? I think the F is calibrated for 62gr from a 16” flat top rifle. Workable. ACOGs are not precision reticle optics, Leupold and Steiner make those in Mil-Dot. For hitting steel it will work. Attached File |
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It's workable. You might be off +/- some yards, but it shouldn't make much of a difference. I've had a TA31 on a 20" Armalite upper for over 10 years. I zeroed at 25 meters for Appleseed, because I intended to shoot both 25-meter and KD events. I never adjusted my hold for 100 or 200 yards, 300 was "close enough," and 400 needed a minor change, usually just holding slightly low. I typically score 45-47/50 on an AQT. |
Posterity! You will never know, how much it cost the present Generation, to preserve your Freedom! I hope you will make a good Use of it. If you do not, I shall repent in Heaven, that I ever took half the Pains to preserve it.---John Adams
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I had a TA31F-G on a 20" A4 and beyond 300 meters it was way over-shooting. I put it on a 16" carbine and the BDC was perfect (the BDC on the TA31F is indeed calibrated for a 16" barrel firing M855). I also have a TA31H-G on a 16" carbine (the TA31H has a BDC calibrated for a 14.5" barrel firing M855) and I do have to hold under just a little at 400 and 500 meters, but it's close enough that it's workable. |
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Originally Posted By Coordinate_Cowboy: Hey all, I’ve got a TA31F that may get pushed into use on a 20” 5.56 rifle. Anyone know how well the BDC will still line up? I think the F is calibrated for 62gr from a 16” flat top rifle. You can zero it with M193 so all the ranges line up for the next 100y mark. Example: tip at 200yds, 300yd tick is 400yds, 400yd stadia is 500yds. It lines up almost perfectly this way. Also, with 75/77gr ammo it CAN line up with the marks okay. It depends where you live(elevation, etc). |
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