Well. I bought that 11.5 fsp barrel today to put in my PSA upper. And the FN CHF barrel needed the fsp chopped.
So here's what the stubbornness of a mule, 3 hours, a couple beers, a leather glove, a bfh, a vice, some punches, 2 wore-the-fuck-out handsaws, some good hand files, a pair of linesman's pliers, and an unGodly ability to hold a piss while I worked in the garage will accomplish.
Could it be possibly better contoured? Yes. But I don't have a dremel or an angle grinder, and the blisters I can feel forming on my right hand are telling me, "Fuck you!" So as long as it fits under the handguard with acceptable clearance, I'm good. Have to take the upper to my brother's house since he has the upper receiver blocks.