Zeroing issues. Can't track it down...

[MistWolf]

How does the wind closest to the shooter affect the bullet the most? Down range, the bullet is travelling at a lower velocity, increasing time in flight, giving conditions more time to change bullet path

[Clod Stomper]

I'll take a stab.

Say for instance that you only have a breeze near the shooter (the first 100 yards). If your range is 400 yards and the breeze pushes your bullet 1 MOA, you are 4 inches (roughly) off at the target.

If however the breeze is only at the target (the last 100 yards) and it moves your bullet 1 MOA, you are only off 1 inch.

I know that there must be a better way to explain it, but that's how I understand it. A wind near the shooter affects the rest of the bullets travel, whereas a wind near the target only affects the bullet when it's near the target, a much shorter time period.

Will

[MistWolf]

That makes sense. You could not have explained it better

[Eurodriver]

This is a good conversation about wind, however I would like to point out that it was absolutely 100% dead the entire time I was at the range. If there was any wind at all, and there wasn't, it would have been coming at a full value from my back to the target anyway.

[Failure2Stop]

There are a whole lot of people givng advice to the OP in this thread saying things that frankly do not need to be said.
The OP is a USMC marksmanship coach and performed well in service competition against other Marines. Marines shoot out to 500 yards for qualification, wind is well covered. He has been given instruction and had to teach people about beating-up ACOGs for adjustments to register.
And above all that, he is shooting 2 MOA with M855! That is at the top of the capability of the weapon and ammo combination.

Euro- you just need to spend some time behind the gun. Anomalies happen, don't let one weird day get in your head. Go shoot.

[JSantoro]

It's been found that if the turret is first adjusted a few clicks past the desired setting, then returned, it settles the reticle before shooting.

Not in this case. Without going down the rabbit hole over it, the ACOG's pin arrangement that floats the prism doesn't allow for this to work, and confounds an otherwise common practice.

Aimpoint, sure.
EO, sure.
SSDS, sure.
PEQ devices, sure.

The ACOG requires a thump to the windage knob with the covers ON to ensure that the detent pin is settled. Otherwise, the pin may be resting in between detents. A thump anywhere generally does the job, but it's the windage one needs to hit to be as certain as possible.

USMC PM Optics has replicated this aspect of these devices across the entire spectrum of Trijicon optics purchased. Even the devices that have no-kidding knobs (no screwdriver or case rim needed to adjust) and were touted as not needing to be thumped, yet displayed a trend to "loading" adjustments if not thumped. That's the SDO (TA11) and the MDO (TA648).

To echo what others have said, given that M855 USED to be 4MOA ammo (it's currently 6MOA ammo; they got a dispensation from the pope to drop the spec 2yrs ago), OP is shooting well inside the gun/ammo capability envelope.

[Eurodriver]

There are a whole lot of people givng advice to the OP in this thread saying things that frankly do not need to be said.
The OP is a USMC marksmanship coach and performed well in service competition against other Marines. Marines shoot out to 500 yards for qualification, wind is well covered. He has been given instruction and had to teach people about beating-up ACOGs for adjustments to register.
And above all that, he is shooting 2 MOA with M855! That is at the top of the capability of the weapon and ammo combination.

Euro- you just need to spend some time behind the gun. Anomalies happen, don't let one weird day get in your head. Go shoot.

Thanks F2S,

While I never want to be unappreciative of someone offering help, advising to rap the ACOG after making adjustments or compensate for wind is basic stuff. Many times at 500 yards I have had to put the BDC tick mark on the next target over in order to compensate for a 15mph full value wind.

I will take it out again this wekk. I'm going to bring a few different types of ammo, a few months ago in Hawaii this rifle shot significantly better with 77gr Black Hills ammo (2 MOA at 200 yards with iron sights) I'll try that and some other commercially available loads just to be sure the ACOG is good to go.

Likewise, I'll shoot 10 round groups at 300 yards and adjust the center of the group from there. I'll also lower my expecations. I guess I got spoiled shooting NM rifles with match ammo. 5" groups at 300 with an optic isn't something to brag about at a match.

Santoro, its nice to know the Corps is still taking care of the Marines.

6 MOA ammo at 300 yards is 18".
The black on the Able target is only 12"...

[SA80Dan]

Thanks F2S,

While I never want to be unappreciative of someone offering help, advising to rap the ACOG after making adjustments or compensate for wind is basic stuff. Many times at 500 yards I have had to put the BDC tick mark on the next target over in order to compensate for a 15mph full value wind......

Apologies for teaching you to suck eggs, Eurodriver....I missed your post #5 above. The only reason I brought up the wind issue was that you said; "I went to the range today to finally sight in some of my ARs at distances further than 50 yards"....this being the internet after all where a lot of people don't ever shoot over 50 yards, thought it was worth mentioning....but obviously doesn't apply to you.

[OMD]

Ditto to the above Euro - sorry for overstating what you already knew - I too read too much into your OP.

[MistWolf]

Not in this case. Without going down the rabbit hole over it, the ACOG's pin arrangement that floats the prism doesn't allow for this to work, and confounds an otherwise common practice...

Thank you. I did not know this