jumpinjoe
Hellcat
What???? You don't have three hands? LOL! LOL! Just jerking your chain a little.
When you said this .... " The issue I'm describing, with the RomeoZero ...is that I cannot see the entire front iron sight ...through the lens of the RomeoZero .... that the body of the RMR blocks my view of the front sight ...that when I try to sight in or aim using the iron sights looking through the RMR lens ... I cannot drop the ball of the front sight fully into the bucket of the rear sight ...before I start losing sight of the front sight." is exactly the definition of NO 100% co-witness.
I guess in the simplest of terms, a 100% co-witness is when you can see the iron sight alignment and picture exactly as intended while at the same time seeing the red dot ..... usually sitting right on top of the front sight as if the dot itself were a target you were holding at the 6:00 position. Depending on the caliber, bbl , cartridge, etc, of the firearm you're mounting the sight to, a dot sitting on top of the front sight (6:00 hold) when viewing a complete sight alignment and picture will basically give you a 'point blank' hold with just the red dot out to distances not typically a concern to CCW firearms users.
As I understand the term, if you cannot see both the front and rear iron sight as they were intended/designed while also seeing the red dot, you do not have 100% co-witnessing. Now, it's not imperative that you must see the irons while using the red dot, only that you should have that capacity if wanted/needed.
I can agree there is some occasional usefulness to the 'lower 1/3' witnessing, but far more versatile on long guns than on handguns due primarily to the much shorter eye relief on the long guns. It's much easier and more effective with less "dropping of your line of sight" with the short eye relief on the long gun.
Hope I've led you correctly and offered clear advice. And best of luck.
Edit: I think 'Lock n Load' just mentioned that third sight I couldn't remember. Be sure to see his post just above mine.
When you said this .... " The issue I'm describing, with the RomeoZero ...is that I cannot see the entire front iron sight ...through the lens of the RomeoZero .... that the body of the RMR blocks my view of the front sight ...that when I try to sight in or aim using the iron sights looking through the RMR lens ... I cannot drop the ball of the front sight fully into the bucket of the rear sight ...before I start losing sight of the front sight." is exactly the definition of NO 100% co-witness.
I guess in the simplest of terms, a 100% co-witness is when you can see the iron sight alignment and picture exactly as intended while at the same time seeing the red dot ..... usually sitting right on top of the front sight as if the dot itself were a target you were holding at the 6:00 position. Depending on the caliber, bbl , cartridge, etc, of the firearm you're mounting the sight to, a dot sitting on top of the front sight (6:00 hold) when viewing a complete sight alignment and picture will basically give you a 'point blank' hold with just the red dot out to distances not typically a concern to CCW firearms users.
As I understand the term, if you cannot see both the front and rear iron sight as they were intended/designed while also seeing the red dot, you do not have 100% co-witnessing. Now, it's not imperative that you must see the irons while using the red dot, only that you should have that capacity if wanted/needed.
I can agree there is some occasional usefulness to the 'lower 1/3' witnessing, but far more versatile on long guns than on handguns due primarily to the much shorter eye relief on the long guns. It's much easier and more effective with less "dropping of your line of sight" with the short eye relief on the long gun.
Hope I've led you correctly and offered clear advice. And best of luck.
Edit: I think 'Lock n Load' just mentioned that third sight I couldn't remember. Be sure to see his post just above mine.