Does not fit - buyer beware - FAB Defense Vanguard M16 MLOK Compatible Picatinny Handguard

I purchased this to install on a Colt LE6920. Unlike Magpul handguards, the bottom piece is what is installed first. I slid the bottom piece forward to latch onto the front cap and then tried to lift the back end up to fit onto the barrel nut. I immediately encountered a problem. The two "wings" on the side -- the two tabs on either side just above the QD points that say "Vanguard" -- would not clear the teeth on the milspec barrel nut. Those wings curve inward and so they do not freely slide over either side of the teeth on the barrel nut. The plastic use on this handguard is VERY rigid so it's not just a matter of bending them out of the way slightly.

Out comes the file! I filed down the top pointy parts of those wings as well as the inside edges. Now I have a new problem. The wings clear the barrel nut but now, no matter how hard I smack the bottom of that handguard, it will not fully engage with the end cap so the barrel nut teeth will seat into the rear of the handguard. I even tried a rubber mallet. No dice. Would not budge. There was some issue with the handguard clearing the sides of the end cap. I figured that was the case because even before filing down those wings the fit on the end cap side was extremely tight.

End result - money wasted because the handguard won't fit and now it's mangled past the point of where my conscience will let me return it. It's now in the parts bin. One day I might find a use for it. I understand there's a +/- spec for fitment on AR15s but this wasn't a frankenstein home build, this was a COLT LE6920. I would have expected it to fit that rifle if it fit anything. This rifle has worked fine with all Magpul handguards, Knights Armament RAS, Troy Battlerail, Midwest Industries Drop-in Mlok rail, Damage Industries Quad Rail, Colt M4 handguards, DS Arms M4 handguards (I use this carbine specifically to test out handguards!). No fitting issues with any of them besides some slight filing needed on the Damage Industries rail to fit the end cap.

It's a shame too because FAB Defense got a lot right on this handguard. There are 4 slots on the side instead of 3 like the Magpul SL. There are two slots at 2 and 10 o'clock for 4 total. Contrary to what has been said elsewhere, there are indeed slots on the bottom too. It's also a shame because this is the first FAB Defense purchase I've ever made and will likely be my last.