Well, it took a dremel and a rubber hammer to get them on, but they are solid. I had to open up the slot that goes around the barrel nut quite a bit, and take some off the the front end, both on the top piece. Beat up the barrel nut and the delta ring a little, but aluma balck took care of that.
I plan on getting at least two more sets, but if they're like this pair, I'll have someone more skilled than I am to install them. Great handguards, at a great price. Calvin at BrightFlashlights.com is great to do business with!