View Full Version : Optic height to clear FSP?
Sorry if this has been asked before, and yes I did use the search function.....:D
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.
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.
http://img.photobucket.com/albums/v374/TOM64/000_0642.jpg
Alpha Sierra
08-15-07, 06:11
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'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.
Here's the reticle, well I hope I can attach it.
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
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
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.
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! :p
Erick Gelhaus
08-15-07, 09:40
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.
Both the LaRue 1.5 SPR mount and the LaRue Aimpoint mount positions the front sight tower in the same place in the optic....Bottom 1/3rd of the tube.
Never had a problem with the fixed front sight tower and the LaRue 1.5 SPR or SPR-E mount. but then again, I don't get "off the bench" all that often :D :
http://demigod.org/~zak/DigiCam/PRM-2007.02/smaller/D101_1057_img.jpg
http://demigod.org/~zak/DigiCam/PRM-2007.02/smaller/D101_1374_img.jpg
http://demigod.org/~zak/DigiCam/PRM-2007.02/smaller/D101_1422_img.jpg
http://demigod.org/~zak/DigiCam/EAG-Carbine-2007/smaller/D101_5351_img.jpg
http://demigod.org/~zak/DigiCam/EAG-Carbine-2007/smaller/D101_5356_img.jpg
http://demigod.org/~zak/DigiCam/EAG-Carbine-2007/smaller/D101_5331_img.jpg
Semper Fi,
Jeff
My Aimpoint has a nice bright dot that keeps my attention, at least that's my excuse:)
Oh and my targets normaly aren't standing still:D :D
http://img.photobucket.com/albums/v374/TOM64/cat.jpg
Different uses and users, I figured out not all things work for all people. I try things and choose what works for me. Best part about this is the OP can try either one or both and Larue will be more than happy to get him what he needs, at least as long as Mark's alive.
Thanks for all the info guys.
I'm not concerned about the FSP being "in the way", I just want to use the BDC/range finding reticle. The pic I posted of the reticle does not do it justice. The horseshoe is much more defined than the pic illustrates and really makes the FSP a non-issue at close range. At longer ranges when I settling it don't even take in the horseshoe or FSP, I focus on the target and center dot.
Well I got the 1.93" high unit and could not be happier.
I'm sure other people have said this before but LaRue mounts are very, very nice. I now see why they get the price they do, they are very well made with those great "guiding" cams on the bottom of the rings.
I was a bit hesitant to buy one but now that I've got it I'm very pleased.
The height of the 1.93" unit is perfect for the optic I have. The entire BDC section of the reticle is very easy to see and is well above the FSP.
Glad to hear it and ya I held off buying LaRue products as long as I could. I now use nothing but their mounts and am fixing to buy my third rail and another mount.
Glad to hear it and ya I held off buying LaRue products as long as I could. I now use nothing but their mounts and am fixing to buy my third rail and another mount.
I have never used their stuff and would like to but they wont open up to any more dealers. I end going with another companies because of the mighty dollar. It must be nice to have so much business lined up that you dont want anyone else selling your stuff.
Pat_Rogers
08-24-07, 05:35
I have used the 1.93 but only to clear PEQ-2A, DBAL's and the like. Otherwise, the 1.50 works better for me as it more closely replicates the height of the Aimpoints (of various flavors) and EOTechs on other guns.
ShiHan- don't cut off your nose to spite your face. Mark is- and has been- at max capacity for more then a few years now. He just put in a new building, bought more machines, hired more people- and he is still saturated with military work.
Adding dealers would only mean more sales- and that is more sales then he can keep up with. This translates into more customers who are pissed off with waiting. If you want good, expect to wait (see Eagle for more. Best kit, longest wait due to mil contracts). Additionally, more dealers presents other logistical problems as well.
He had a choice to make, and he made it based on his business plan (which is apparently working pretty well...)
His mounts, rails and even 'dillo's are exceptionally well made, and made with the input of those who use them. I have a bit more then first hand knowledge here.
It is a free market, and anyone can buy what they want. From my POV, i have seen enough of the other stuff fail to make me understand that if Larue is an option- Larue is the Answer.
Just my nickel's worth of blather...
Well I'm starting a 4 day weekend that I desperately needed. :D
But the gun club is closed for maintenance on the front gate so it's closed.:mad:
No zero today. I'm on for tomorrow to zero it then head up to the mountains on Sunday (since no shoot in Pueblo) for some longer range shooting. My club only has a 200 yard range. It's good for a zero but not to see if my gear (and I) and still engage at 300 - 400 yards, or more if I feel froggy.
I have used the 1.93 but only to clear PEQ-2A, DBAL's and the like. Otherwise, the 1.50 works better for me as it more closely replicates the height of the Aimpoints (of various flavors) and EOTechs on other guns.
ShiHan- don't cut off your nose to spite your face. Mark is- and has been- at max capacity for more then a few years now. He just put in a new building, bought more machines, hired more people- and he is still saturated with military work.
Adding dealers would only mean more sales- and that is more sales then he can keep up with. This translates into more customers who are pissed off with waiting. If you want good, expect to wait (see Eagle for more. Best kit, longest wait due to mil contracts). Additionally, more dealers presents other logistical problems as well.
He had a choice to make, and he made it based on his business plan (which is apparently working pretty well...)
His mounts, rails and even 'dillo's are exceptionally well made, and made with the input of those who use them. I have a bit more then first hand knowledge here.
It is a free market, and anyone can buy what they want. From my POV, i have seen enough of the other stuff fail to make me understand that if Larue is an option- Larue is the Answer.
Just my nickel's worth of blather...
Very good point Pat, I guess I will be ordering that SPR mount from him.
Thanks
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