Optic height to clear FSP?

[Low Drag]

Sorry if this has been asked before, and yes I did use the search function.....

What is the height an optic needs to be (center height) to clear the front sight post on an A4 type carbine?

Mine is a RRA mid length and fixed FS assembly. I have an IOR (30mm) with CQB reticle and ranging/BDC that would be nice to use if I can make it down to Pueblo for the carbine match.

I'm looking at the LaRue mounts for the M4, they have 2 models. One is 1.93" high and I think the other is 1.5" high.

I need to get it mounted just a bit further forward than I have now to get a good purchase on the charging handle and to get a more natural cheek weld. Thus far I could adjust to the new cheek weld (I'm nose to charging handle guy) but not getting a good grip on the charging handle ticks me off.

Thanks in advance.

[TWR]

The 1.93 mount is perfect for a low powered scope. I just put a Leupold 1.5-5 in one and it works perfectly.

[Alpha Sierra]

I'm confused. Do you actually need to physically clear the front sight, or do you just want the sight our of your scope's FOV?

I have personally never found the front sight to be a distraction when seen through magnified or non-magnified optics. In any case, once magnification reaches around 3X, the front sight becomes a almost invisible blur. Anything higher than 3X and you cannot see the front sight.

[Low Drag]

I'm confused. Do you actually need to physically clear the front sight, or do you just want the sight our of your scope's FOV?

I have personally never found the front sight to be a distraction when seen through magnified or non-magnified optics. In any case, once magnification reaches around 3X, the front sight becomes a almost invisible blur. Anything higher than 3X and you cannot see the front sight.

I just want to ensure the cross hairs to be above the front sight post so I have a better FOV.

As I said, the reason I'm asking is the lower vertical cross hair has the ranging/bdc on it. It would be nice if it could clear the FSP. I'll see if I can find a pic of it and it will make more sense.


Thanks for the replies guys.

TWR, if the standard height unit does not give me the clearance I'm going with the one you have.

[Low Drag]

Here's the reticle, well I hope I can attach it.

[USMC03]

LowDrag,


I have (2) S&B 1.1-4x Short Dots in LaRue 1.5 SPR-E mounts and a Leupold 1.5-5x in a LaRue 1.5 SPR mount.

At 1.1x or 1.5x you can see the front sight post but it is in the lower 1/3rd of the tube and the front sight tower does NOT interfer with the field of view and is not close to the cross hair of the reticle.

As the magnification power goes up the front sight tower blurs out and gets lower in the field of view.

I have had ZERO issues using a LaRue 1.5 mount in conjuction with a carbine that has a fixed (ie. non folding) front sight tower and a lower powered magnified optic.


Semper Fi,
Jeff

[USMC03]

If you can make it to this match: https://www.m4carbine.net/showthread.php?t=2475

On the 26th of this month let me know and I'll bring one of my M4's with a low powered optic and LaRue 1.5" SPR.



Semper Fi,
Jeff

[TWR]

The FSB does not bother me with my Aimpoint but it does with a low powered scope. I also have a 1.5 LaRue mount with a Leupold 3.5-10 scope in it. On 3.5 power it cannot be seen until you turn and the sun shines on the ramp of the FSB, then it throws a glare into my scope. I've fought this problem with several mounting options for a while now, usually wound up grinding off the FSB on a scoped gun.

If the rifle has a fixed FSB I will use the 1.93 mount if it's a folding sight I will use the 1.5, BTW when zeroed at 50 yards it makes 1/4" difference at 100 yards between the 2 mounts. I need to shoot further and see what happens. If you can use the 1.5 then no problem but if you like a clean sight picture the 1.93 mount works.

[Low Drag]

LowDrag,


I have (2) S&B 1.1-4x Short Dots in LaRue 1.5 SPR-E mounts and a Leupold 1.5-5x in a LaRue 1.5 SPR mount.

At 1.1x or 1.5x you can see the front sight post but it is in the lower 1/3rd of the tube and the front sight tower does NOT interfer with the field of view and is not close to the cross hair of the reticle.

As the magnification power goes up the front sight tower blurs out and gets lower in the field of view.

I have had ZERO issues using a LaRue 1.5 mount in conjuction with a carbine that has a fixed (ie. non folding) front sight tower and a lower powered magnified optic.


Semper Fi,
Jeff

Thanks a million! That's what I wanted to know. I knew the LaRue 1.93" high would clear for sure but want the optic a low as I can get it. If the 1.5" high unit easily clears the FSP I'm in business.

Even if I don't get the mount before the match I can still use what I have, it's just not optimal.

But if I totally blow the match, don't be posting it here!

[Erick Gelhaus]

fwiw, my experience mirrors that of USMC03. Two S+B scopes, one in a SPR-E mount and the other in a SPR. I do not find the FSB to be 'visually annoying' with either of them at low power.