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Yea I wish I could do that, which is what we used to do in the Marine Corps. I am just so constricted by local ranges that it is hard to find a range past 200 yards or even a range with a 36 yd target. I am just going to have to perform the 100 yard zero and the BDC may be off a tad but that's alright. I'm not attempting to be a sub MOA shooter with this optic. I only purchased it because I have trained with it for years and feel comfortable with it.Quote:
Originally Posted by TehLlama
Quote:
Originally Posted by TF82
They may help and I have thought about giving those a try at 25 yards and getting a nice group just a tad high in the 100M circle. Basically I would be trying to compensate for the meters to yards and get POI a little high for that purpose.
POA/POI at 100 yards is going to be just fine.
The bullet hangs at the line of sight for quite a while around 100 yards/meters, and will be within the adjustment capability of the optic.
The best thing to do is to fine-tune your elevation at long range when the opportunity presents itself.
Does your range not allow you to go beyond the 100 yd mark with your own little target stand? Go on a day with no one there and cheat back your end and the target end to get that last nine yards.
Our just don't worry about it and go for 100 yards even. It's a very small difference. Depending on your ammo used your may not be able to tell.
The range does go to 200M so I could zero at the 100 yard range and make the adjustments at 200meters. That would hopefully help me get a better zero. Either way like others have said the difference isn't going to be insane and I am not precision shooting with an ACOG.Quote:
Originally Posted by cbx
Just zero at 100 yards, The difference is like .2 MOA.Quote:
Originally Posted by equilibrium
If your COG has the chevron reticle, it will make your 200M shooting less than precise since the 200 is at the apex of the bottom part of the chevron.Quote:
Originally Posted by equilibrium
http://i139.photobucket.com/albums/q...Technical1.jpg
This tends to make me hold a little high on my desired target, especially if the fiberoptic isn't taped off.
Wind-drift is also a bit more shakey at 200 since there isn't a readily referenceable wind-hold in the cog and lots of well-meaning folks wind up dialing in an atmospheric unwittingly.
The tendency to hold a bit high with them applies to me too, the TA31 reticle is one of the few I never bother to zero at 50 or 200m if I can help it (even on one of our Table I/II shoots somebody insisted on refining zeroes at 200yd for table 2, unsurprisingly myself and two guys in my fireteam who agreed we should leave it alone were three of the top four scores on that table 2). I'd literally rather zero the ACOG at 36yd and be off some vertically than be in doubt for both trying to make the crotch of chevron be the POA and tend to be off (aggravated by shooting position NPOA changes). When I get the chance, I'll zero for 100m in a partially supported sitting as that tends to produce ideal results for me. I'm not unwilling to make windage adjustments at 200yd/200m, but that's only in dead still wind conditions; for that type of optic if I'm on at 36yd it's close, and on at 100yd/100m is perfect... I'm much more likely to be a source of error beyond that because being so tight to the optic means that I can make a half millimeter move of cornea position and do more to affect POI relative to sight picture than making one-click adjustments (especially since forgetting to smack the turrets tight just once is plenty to throw the whole data set off).Quote:
Originally Posted by Failure2Stop
Does your range go to 300 yards? If so, you can zero at 100 yards, then take it out 300 and make adjustments so that the 300m is zeroed at 300 yards. That should get you close are longer ranges.
Just saw that you said it goes out to 200yd.
I don't recommend this.Quote:
Originally Posted by Zane1844
A 100 yard zero is closer to a 100 meter zero than a 300 yard zero is to a 300 meter zero for the ACOG BDC to be correct at longer range.
If you zero at 91.44 meters (100 yards), you will show around 15 inches of drop at 300 meters.
If you zero at 100 meters, you will show pretty much the same at 300 meters.
If you change to a 300 yard (274 meters) zero, your 100 meter zero will be off by 4 inches, and your 300 meter zero by about 3 inches. Not a huge deal on the 300 for most folks, but your 600 would be off by over 20 inches. Again, most don't actually shoot that far, but if I can avoid putting that much error into the optic I generally won't.
*The above based on M855 at 2850-2950 fps*
It seems counter-intuitive, but a 100 yard zero instead of a 100 meter zero will show no appreciable difference at 600 meters.
Still, you don't know exactly where the bullet is going to go until you shoot it at actual distance.