Upper Marking Question

[wildhaggis96]

I bought a flat-top upper and it has an "L" stamped on the aft side of the rear pin boss. What does this indicate? This upper fits both my Colt and DPMS lowers, although it will not fit my RRA lower.

My question would be directed to the manufacturer, but I don't remember where I bought it. Any input would be appreciated.

Thanks

[tiger seven]

This thread lists some forge markings on uppers: http://m4carbine.net/showthread.php?t=5357

I have no personal experience with RRA lowers, but I've heard from multiple sources that they can be much tighter than some other lowers. Many people have reported difficulties in putting non-RRA uppers on RRA lowers.

Derek