Magnifier induced POI shift

[frankprstw]

Hi fellow shooters
I am running sig romeo 4H and juliet 4x magnifier combo on my Colt 6720.
It turns out when I flip the magnifier on, the POI shifts about 5inch high at 100y.

I tried the adjusting knobs on the magnifier, it does move the dot around inside FOV, but the adjustment does not affect POI shift.

Both Wolf Gold 55FMJ and IMI Razor Core 77OTM were behaving this way, would you point me a direction to fix this?

Thank you

Francis

 

[kl3309]

Sounds like parallax issues from not having the same cheekweld when using the magnifier as opposed to just the red dot? Make a point to keep the same position on the stock linearly as well as vertically when switching from one to the other. Re-locate the magnifier/optic combo forwards or back if you have to adjust for eye relief.

 

[S197]

How many yards on the non magnified shots?

 

[M4guru]

Did you zero magnified or unmagnified?

 

[jeffl838]

It looks like there's a 4 minute difference between the magnifier on and magnifier off. A 4 minute shift actually isn't that bad. It could be much worse with other magnifier/optic combos. I'd zero with the magnifier at 200 or 250, and just know that if you shoot unmagnified you'll be zeroed at around 100.

The only cure I can think of that might cure this (I haven't tried it, I've just learned to deal with it) is shimming the magnifier to change the angle/height that the magnifier "sees" the red dot at? I don't even know if this will actually work.

 

[loveha]

From what Sig says in the manual, the magnifier does not change POI.
I have the same combo on my SBR. Have not tried unmagnified. Just sighted it in and called it a day.
So the only thing I can think of is user induced parralax when changing eye relief. I think I adjusted the height of my magnifier up?
If weather is good, I'll go try my setup on Sunday.

 

[M4guru]

A 4 MOA shift is absolutely horrendous for the record and absolutely not normal. I’ve been using these things (like for real when it mattered) since they came out. Got issued Aimpoint and EOtech magnifiers and haven’t ever even heard of shift like that. Generally when guys zero magnified they’re fine, when they try to zero unmagnified and drop the 3x behind it they had more issues.

 

[jeffl838]

A 4 MOA shift is absolutely horrendous for the record and absolutely not normal. I’ve been using these things (like for real when it mattered) since they came out. Got issued Aimpoint and EOtech magnifiers and haven’t ever even heard of shift like that. Generally when guys zero magnified they’re fine, when they try to zero unmagnified and drop the 3x behind it they had more issues.

Yeah man, you’re the only guy here that’s been issued aimpoints/eotechs/magnifiers for war /sarcasm

This is a known issue with magnifier/rds combos. It’s in military publications and tacsops. You’re ignorant. Empirical info is definitely on whatever portal your plugged into. You said it yourself… Most people don’t notice if they zero it magnified… because they won’t shoot at distance without the magnifier and a 4 minute shift in the right direction is the difference between a 200m zero and like a minute low from a 100m zero (still getting all your hits 200 and in)

 

[frankprstw]

Sounds like parallax issues from not having the same cheekweld when using the magnifier as opposed to just the red dot? Make a point to keep the same position on the stock linearly as well as vertically when switching from one to the other. Re-locate the magnifier/optic combo forwards or back if you have to adjust for eye relief.

Yes I did tape a bead on the stock for a quick reference when I line up my sight.

When using magnifier however the eye relief would require me leaning further forward. I took extra caution on sight pictures when sighting in.

The positions of the component are pretty tied up as I tried to have the dot, magnifier and BUIS everybody on the receiver rail.

 

[frankprstw]

How many yards on the non magnified shots?

Both at 100.
I got lucky, it’s typically around 2 MOA.

 

[frankprstw]

Did you zero magnified or unmagnified?

Zeroed unmagnified at 50 and verify both at 100. As a result the unmagnified group is slightly higher off the center.

 

[frankprstw]

thank you guys
It might have something to do with my setup. I bought cheap separated riser sections to raise the sights so to clear the laser upfront.

Ordered a PRI one piece, hopefully it helps to alleviate somehow. If not I will just zero magnified.

This is what I see before raising the sights

This is what I have now

 

[jeffl838]

I think all Romeo 4's are compatible with t1 footprint mounts? I'd ditch the sig QD and get a geissele 1.93