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9/22/2017 12:11:25 AM
Posted: 11/16/2003 6:56:16 PM EDT
I'm not going to buy the new barrel unless I can put an ACOG on it. So what ACOG matches the drop of the 77gr? I have heard that some are close. I know that JP sells a TA01 made specifically for 77gr, but I want the BAC.

Help please?
Link Posted: 11/17/2003 1:50:03 AM EDT
TA11 with .308 reticle. VERY close match.
Link Posted: 11/17/2003 5:50:46 AM EDT
Assuming you are going to mount to a flattop, the BDC that most closely matches the 5.56mm 77gr. trajectory is the .308 TA11C or TA01B for carry handle (not the TA11E for flattop). However, I would use the 62gr. 14.5" BDC if it were me (TA01NSN, TA31F, TA11F, TA11F-A). This can be tweaked to be almost as close a match as the TA11C; but you can still use it with 55gr and 62gr 5.56mm ammo. The TA11C is a poor match for anything but the heavy 5.56mm. Check the [url=http://www.ar15.com/forums/topic.html?b=3&f=18&t=152794]Big ACOG BDC Chart[/url] thread tacked above. The 75gr Hornady has a profile very similar to the 77gr Nosler. (Though if you are using NATO-spec 77gr out of a 16" barrel;, you should use the charted stats for the 75gr out of a 20" barrel as the NATO-spec is about 100fps hotter)
Link Posted: 11/17/2003 12:10:46 PM EDT
[Last Edit: 11/17/2003 12:12:34 PM EDT by Yojimbo]
I'm also seriously considering a TA31, Donut of of Death[:D], for my 16", 1/7 carbine. I'll be using a it on a SIR 50 with either the ARMS 19s or the TA51. I wanted a general purpose optic to handle the various ammo from 55 gr through 77 gr. I eventually want to to put it on a 20" M16A4 clone but it may be a while before I put it together so it'll be on my 16" carbine until then. It looks like from your ACOG BDC posts that it will work but will the TA31 be okay for this setup or will I be BDC be pretty useless for me?
Link Posted: 11/17/2003 2:10:19 PM EDT
You can tweak the TA31 BDC to get close to almost any 5.56mm load/mount/barrel (though it doesn't match the heavier stuff as well as the other BDCs as you can see). If you can measure the height over bore of the ARMS#19S, SIR, and ACOG combo, I'll give you some more solid numbers but it should be closer to the original carry handle height which actually works for you with the TA31.
Link Posted: 11/17/2003 8:04:13 PM EDT
16" 1/7 barrel with MK 262 with Nosler 77 grain bullet with a TA31 scope on a 19S mount. 50 yards Top of donut (make this your zero) 100 yards 1.2 inch over donut 200 yards with in the top edge of donut ring 300 yards bottom of inner circle 400-600 hashes less than MOA under the hash mark. 700-800 should be closer to the hash. This is an estimate only. The BC of the 77 grain Nosler is much different than the 75 Hornady. Nosler is .340
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