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[davidjinks]

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[iNeXile]

What rear sight are you using?
With a standard A2 type sight, the Z setting is used to zero a 20" barrel at 25 meters.

[davidjinks]

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[iNeXile]

The KAC 200-600 is not "made" for a 50 yard zero, thought the "200" mark will be close. When I had mine I just zeroed as per the directions (Z mark and zero to 27 yards) and it was an awesome BUIS.

If you want to shoot it at 50 or 100, just keep it on the Z mark and it will just be off by a few inches. It was made to be a combat sight not a target sight.

From your post it sounds like you did it backwards. It should be Z at 25meters (27yards) and 200 for 50 yards. Zero at Z at the 25range and you should be fine.

[Tweak]

is the receiver on the same plane as the handguard?

[davidjinks]

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[davidjinks]

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[iNeXile]

Sorry, from your post it sounded like you zeroed at 50 yards set to the Z mark.
If those POIs are in feet then something else is seriously amiss.

I'd check the rail alignment. run a straight edge down the top and make sure it's not angled down.

ETA: You posted as I was typing, well that blows the misalignment theory out. Sorry, I got nothing.

[Tweak]

you'll want to check the height over the bore on your front sight.

[davidjinks]

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[Tweak]

That's the distance from the center of the bore to the top of the "UP" marked flat on the FSB.

[davidjinks]

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[Tweak]

if those 6920s are set up the same as the problem rifle (flattop and rail) and the sights are the same I would swap the known good sights onto the problem rifle.

[davidjinks]

I will do that as well.



if those 6920s are set up the same as the problem rifle (flattop and rail) and the sights are the same I would swap the known good sights onto the problem rifle.

[Tweak]

with that much of an error you can just boresight the upper and save the trip to the range and the ammo. Boresight the problem one as it sits as a baseline.

[alex71]

I think it is because it is designed for a 200 yard zero not a 50.

[davidjinks]

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[JSantoro]

http://www.knightarmco.com/manuals/600m.pdf

Page 1, paragraph 2. The "Z" setting is one click past the 300m mark, toward the 400. That's gonna put a lot of elevation on the round, which you'd need for a shorter barrel. But, that's most likely too much, even for a barrel 4" shorter than carbine-length, hence the reason the front sight ended up so far up. It's trying to push the muzzle down for you, but doesn't have the range of motion needed to do so with the Z setting of the rear.

For what you're trying to accomplish, use the 200m mark, as iN specified. His statement about not being "made" for a 50yd zero is specific to the sight settings, and makes sense because he couched it in the right way.

The statement that these sights aren't made for close-aboard shooting in the general sense or 50yd in particular is incorrect, as a stand-alone statement. The ballistics of a 50/200 or a 300m BZO and the initial, upward LOS crossovers that they require make that abundantly clear, so the only reason you might not be tracking is because that statement is patently false, as posted. They pretty much HAVE to work close-in, else none of the 25m field-expedient methods would work in the first place.

However, since we're talking about FEET.....dayum! Only way I could see that happening is if you somehow had an extra turn on the rear, like how one can be 8/3 (or 6/3, depending) on an A2 rear drum, and think that they're on the 300, when in fact they're on the 800 (or 600) and just didn't catch it. I don't know if that's physically possible with these sights; I'd have to check, and can't, now. I've used these and use micros on my guns, but it's never occurred to me to try to over-rotate it, so I have no idea and hope maybe somebody has one close at hand and can confirm or eliminate this as a possibility.

So, kinda spitballing, here, but were it me....

Given that I have nothing impinging the barrel inside the FF, that the rail is aligned properly with the upper receiver (spoken to, already) and that everything else is aparrently kosher, I'd turn clockwise on that rear sight elevation, all the way. Take it to it's lowest limit of travel, then take it back up to 200. Attempt to re-zero based on that.

[davidjinks]

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[Failure2Stop]

David, feel free to bring the trouble gun to class this weekend. We have plenty of sights to swap out to isolate, and hopefully correct, your issue.

[davidjinks]

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[Cameron]

1.5 FEET high at 50yards. It sounds like you have a barrel/rail alignment issue. I would re-install the rail and see if things change.

Cameron

[davidjinks]

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