Co-witnessing heights, please help

[ifilef]

Thanks for input thus far.

I figure if one is properly zeroed the other should follow easily. I don't want to zero both independently and probably waste time and ammo.

In making that determination, what are opinions of which zeros more easily? Assume for the question that neither have been truly zeroed, but that a default 'battle sight zero' (not sure if correct designation) has been done to the irons so that rear sight middle of horizontal plane, and front sight post is flush with housing, and that RD is fresh out of box?

Where to go from there? How would you do it? Opinions welcome.

[peacedivision]

Zero your irons, install the red dot. zero the RDS off your irons, fire a few rounds to confirm, done.

[ifilef]

Zero your irons, install the red dot. zero the RDS off your irons, fire a few rounds to confirm, done.

I am going to follow your advice-for the most part.

However, wouldn't it be better to mount the RDS for 1/3 co-witness, have unit turned off, sight the irons through the RD, then turn on RD and zero it off the irons?

But wait...I guess that I would have to change cheek weld so that dot comes down to lower 1/3 and sits atop the FS post?

Sorry, I am new to this and it's a bit confusing to me.

[peacedivision]

You're over thinking it Zero the irons, zero the RDS off the irons, shoot to confirm and call it a day.

[ifilef]

I already have RDS mounted, but with high riser for absolute co-witness...it looks pretty good without even sighting in.

I am going to have to remove from rail anyway because change of risers to enable 1/3 co-witness.

So, you are saying, that I should keep to your original advice and sight in irons first as if no RDS existed, then mount RDS and zero it to irons? I am not at the range but at home and can't wait to mount RDS anyway set for 1/3 and see straight-through vs. RD placement when using irons with RD on...

My guess is that when I change risers RD will be in middle of RD field but irons should be in lower 1/3, but then when I change my viewing angle/cheek weld for sighting picture through irons that it should be atop FPS?

[BucDan]

I am going to follow your advice-for the most part.

However, wouldn't it be better to mount the RDS for 1/3 co-witness, have unit turned off, sight the irons through the RD, then turn on RD and zero it off the irons?

But wait...I guess that I would have to change cheek weld so that dot comes down to lower 1/3 and sits atop the FS post?

Sorry, I am new to this and it's a bit confusing to me.

You're over complicating it. Thinking too hard about it. Follow peacedivision's advice and you'll be good to go. You'll understand when you have the optic in hand.

[peacedivision]

My guess is that when I change risers RD will be in middle of RD field but irons should be in lower 1/3, but then when I change my viewing angle/cheek weld for sighting picture through irons that it should be atop FPS?

Correct

[BucDan]

I already have RDS mounted, but with high riser for absolute co-witness...it looks pretty good without even sighting in.

I am going to have to remove from rail anyway because change of risers to enable 1/3 co-witness.

So, you are saying, that I should keep to your original advice and sight in irons first as if no RDS existed, then mount RDS and zero it to irons? I am not at the range but at home and can't wait to mount RDS anyway set for 1/3 and see straight-through vs. RD placement when using irons with RD on...

My guess is that when I change risers RD will be in middle of RD field but irons should be in lower 1/3, but then when I change my viewing angle/cheek weld for sighting picture through irons that it should be atop FPS?

Yes, you'll have to adjust your cheek weld SLIGHTLY. You're first question, that is correct.... do just that.

You don't need to be at the range to zero the RDS. The range is only needed to confirm.

Second question, yes that is correct.

[peacedivision]

Pretty simple summary

[ifilef]

Thanks a lot for responses.

Okay, I am going to add the supplied shim to the high riser and check things out.

The problem is that neither RDS nor irons are sighted in for zero, though the irons are preset by me to a 'battle sight zero'.

[ifilef]

Pretty simple summary

Fine illustration, peacedivision. Thank you.

[ifilef]

re: 1/3 co-witness

So, when adjusting the RD to the irons, I will have to drop line of sight so that red dot sits atop FPS in that sight picture?

Later: After inserting the shim between the high riser and the sight, and then mounting on the rail, when I look through the RDS field the RD is in center and well above FPS, and when I lower my cheek/chin slightly it does sit nearly atop the FPS. I think that I understand now after viewing a bunch of YouTube videos and this thread as that is how it should be.

I will remember the F-O-R-S acronym (front opposite, rear same) for the iron sights, but it may be opposite when mating the RD adjustment to it That will be trial and error today at the range, but I will be able to see adjustment to the front post sight reference without firing a shot. Then shoot and fine-tune.

Will also have to remember that when re-positioning red dot to match atop FPS, I must lower cheek well/line of sight to get proper iron sight picture for that adjustment. Please correct me if I am wrong.

Thanks!

[PrimaryArms]

Co-witnessing heights, please help

http://youtu.be/ogX-cIx9hpk

Hope this helps.
Might want to look at our micro dots they are great.

https://www.primaryarms.com/Red-Dot-Sights-Primary-Arms-s/903.htm

Dimitri

[ifilef]

Yes, thank you. Have seen the video a number of times and found it to be helpful. Already have a newly-purchased Vortex Sparc.

In any event, it seems I've wasted a bit of ammo trying to zero my iron sights, which are Troy micro battlefield flip-up.

Got the rifle in a trade and noticed the rear sight DOA was set off quite a bit to the left side. I should've left it there- instead I set for a battle-sight zero and ending up shooting to the right of target at 50 yds. So it eventually ended up to the left and quite a bit.

I'm not even sure these are the correct iron sights for my JD upper with Centurion Quad Rail. I really like the rifle but I've read elsewhere micros are for higher than normal flat top rails than usual on M4. Don't really know if the quad rail fits in such a category-maybe or seems that it does not and is of standard height.

I also had initially set micro FSP (v-post, M4) for battle-sight zero, too. Another mistake.

Had to end up adjusting that numerous times as well-it is now a couple of revolutions below flush with the housing. I still am not convinced the sights are zeroed though I did hit the bullseye a couple of times in a very small Caldwell target at 50 yds.

I place the front sight post (FSP) at 6 o'clock position for purposes of sight picture.