Sights for a 10.5" - 11.5" rifle

[bigdave73]

Any thoughts on what combination works best on these length of barreled uppers? I've tried a number of combinations but it seems that I have to bury the front sight in the housing to get a 100 yard zero. Such is the case with both a LWRC 10.5 with the barrel mounted front sight (traditional) and a custom built bushmaster 11.5 barrel and a free floating forend and folding sights mounted on the same plane. Any help or advice would be appreciated.

[rob_s]

Aimpoint Micro!

:p

[lanceriley]

try zeroing @50 yards iron sight

[markm]

try zeroing @50 yards iron sight

That would make his problem worse.

[markm]

I know what you mean. Generally, on the carbean sight radius, I'm dialing my sight way down to get the POI right too.

My Colt and Sabre uppers are close to the mechanical zero though.

You might try measuring your Front sight post to make sure none of them are that damned aftermarket tall version. I have an upper that had one of those ****ing things installed. I was having to bottom that thing out before I discovered some retard had a tall post installed on it.

Good luck.

[lanceriley]

maybe you have a very high front sight post.

[Furious]

ACOG compact

[Bulldog1967]

Aimpoint Micro!

:p

Yup I concur...

[K9-Bob]

How about an "F" marked FSB? Would that also make the problem worse?

[markm]

How about an "F" marked FSB? Would that also make the problem worse?

I always get this messed up...

I THINK... that the F marked FSB has a Higher "shelf". Thus, switching to an F from a standard FSB (if possible), all things equal, would put the POI lower at mechanical zero vs a standard FSB with the sight post at mechanical zero.

This is why people with regular FSBs and flat tops often have to buy a taller sight post. The standard sight at mechanical zero in a regular FSB puts the POI too high.

[lanceriley]

maybe your FSB is out of spec. it's not the old FSB nor is it the F marked FSB. maybe it's just very high. so when you go back to the F marked FSB it's just right.


have you checked your upper reciever? maybe not up to spec?

[Col_Crocs]

Optics, I would go with an Eotech. 551 would look great on your 11.5 upper.
Check the FSB if it's an F FSB as stated above.
You might also want to sand down your front sight to almost a sharpened pencil point. Ive seen this done on a couple of friends' guns and tried them and they were great to shoot. Makes shooting longer ranges on your iron sights much easier and more accurate.
BTw, custom 11.5? What do you mean? A cut down barrel? What length/type was it originally?

[bigdave73]

Just to update: the LWRC 10.5" A1 upper has a "F" marked FSB so that can't be the culprit. The second is a Bushy 11.5" 1/9 heavy contour barrel attached to a Vltor MUR upper with a Troy FF forend. The sights are same plane mounted. Both have optics mounted. One has the EOTech and the other an Aimpoint. The optics are squared away, it's the iron sights that are the issue. I appreciate everyone contributing to this and giving ideas or suggestions.

[lanceriley]

i don't want to imply.... but have you tried asking somebody to zero it?

[bigdave73]

With the LWRC you can't just swap FSB's due to the gas system and I've been sighting in AR's for about 30 years now between the military and my current LE position. Again, thanks everyone.