Rear BUIS in front of, or in back of, the optic?

[john c]

@john c, the easy answer is send it to ATEI and have them mill your G45 for Acro with their Shimsight.



EDIT: Adding better pic (note this is a Glock 20)


Otherwise I strongly prefer irons in front for the reasons @GJM mentioned.

This really compelling. Thank you. I saw the shimsight on their website, but didn't really grok it.

I doesn't look like the shimsight can be adjusted for zero, right? Is that a problem?

[john c]

There’s one caveat to that.

If you put the irons forward, you get use of your full window for dot tracking. The dot is still visible with irons forward just like if you taped the lens.

If you put irons rear, you LOSE WINDOW because you can’t see the projected dot.

The smaller the window, the bigger the difference.

That’s my strong preference for irons forward on a small window optic.

I think this is how the porpoise wave thing started when people had huge rear sights and RMRs.

You had to tilt muzzle up or else you couldn’t pick up the dot until later because blocked by the rear tall irons.

This is some seriously great insight. I really appreciate it.

[john c]

I've got 4 with the iron in front and don't really notice it being any better. My most recent 2 have the iron behind optic. It could be that I'm just use to it by now

What optics are you using? If you're using the ACRO, who did you use to get the BUIS to the rear?

[Clusterfrack]

This really compelling. Thank you. I saw the shimsight on their website, but didn't really grok it.

I doesn't look like the shimsight can be adjusted for zero, right? Is that a problem?

No windage adjustment. It's centered, and has a good POI at 15-20 yds. Elevation of course is adjusted by height of the front.

[Caballoflaco]

No windage adjustment. It's centered, and has a good POI at 15-20 yds. Elevation of course is adjusted by height of the front.

If somebody didn’t mind a wider notch they could file one side of the notch to move point of impact. But, man that would be a PIA as far as taking the optic off, filing, reinstalling and checking zero then maybe doing that a couple of times until it’s where you want it.

I would say it’s doable but with a large investment in fiddle fuckery. And I generally don’t like fiddle fuckery.

[JCN]

If somebody didn’t mind a wider notch they could file one side of the notch to move point of impact. But, man that would be a PIA as far as taking the optic off, filing, reinstalling and checking zero then maybe doing that a couple of times until it’s where you want it.

I would say it’s doable but with a large investment in fiddle fuckery. And I generally don’t like fiddle fuckery.

I would imagine it would be close by virtue of being centered in the slide.

You could mock it up with a Wheeler laser and make some adjustment if needed with the optic off. But again I’d be surprised if it would be off enough stock to matter.

Where you’d probably be able to Micro adjust would be in the rotation of the front sight for a Glock.

There’s often a little ability to rotate the front sight a few degrees left or right to get some windage adjustment.

For other guns with a driftable front, obviously no issue.

[rayrevolver]

ATEI Shim sight can go in-front or behind the optic, fielders choice.

[Utm]

What optics are you using? If you're using the ACRO, who did you use to get the BUIS to the rear?

I've got all trijicon rmr's

[HeavyDuty]

I like the irons in front of the RDS because it channels my inner Detonics Combat Master.

(Seriously, I prefer the view through the RDS.)

[CCT125US]

There’s one caveat to that.

If you put the irons forward, you get use of your full window for dot tracking. The dot is still visible with irons forward just like if you taped the lens.

If you put irons rear, you LOSE WINDOW because you can’t see the projected dot.

The smaller the window, the bigger the difference.

That’s my strong preference for irons forward on a small window optic.

I think this is how the porpoise wave thing started when people had huge rear sights and RMRs.

You had to tilt muzzle up or else you couldn’t pick up the dot until later because blocked by the rear tall irons.

This is gold. I went from an optic / no BUIS to the same optic with too tall of a rear and a sail front, and the visual difference is huge.