BCM Lightweight - Front Sight Height?

[HGM22]

Anyone know if the front sights on BCM's lightweight uppers co-witness properly? I know the Colt lightweight carbine doesn't use F-marked FSBs so must use taller front sight posts. Does the BCM use F-marked FSB, taller front sight post, or neither?

 

[briansmithwins]

Properly made F type FSB.

At least my 3-4 year old one is made that way.

BSW

 

[jakk280rem]

*
Mil-Spec F-Marked Forged Front Sight Bases

Mil-Spec for rifles issued to the troops require taller front sight bases on all flat top AR rifles. Many commercial offerings use M16A2 height front sight bases on all of their barrels regardless of what type of upper it is installed on. As a result, owners of rifles and carbines with the flat top receiver configuration can have problems getting a proper 'zero' for elevation with Mil-Spec back up iron sights. As all of the BCM uppers are built for flat top uppers, all have the proper Mil-Spec F marked front sight base to insure the correct height for iron sight zeroing when using military iron sights. Mil-Spec taper pins secure the forged front sight base with the sling swivel secured by tubular rivets.

From their website.
Bolded for emphasis.

 

[md7]

I could be mistaken, but I think the barrel on the bcm lightweight profile bbl (with fsb) is standard diameter where the fsb is attached. Someone please correct me if I'm off on that.

They do utilize f marked fsb's on their lightweight barrels. That I do know.

 

[otrman]

Has nothing to do with barrel profile. Re-read above quote in post #3

 

[HammsBeer]

The BCM lightweight barrels use an F marked front sight and will zero just fine with standard rear sights. Barrel diameter is LW under the front sight (.625").