Well, now that I've committed to having one installed on my new build, just how good are they?  Model 1 Sales said that it'd be installed with the set screws, I really wanted it drilled and pinned but whatever.  Are the set screws going to hold it on ok or will it turn out of alingment, should I remove one screw at a time  and drill a small hole for the screw to sink into when it's tightened up?  Those of you that have em' let me know, do you like em' or are you sorry that you went with a folding front?

Quoted: should I remove one screw at a time  and drill a small hole for the screw to sink into when it's tightened up?

Don't have one, but doing the above properly should make it less prone to moving.  Nothing beats the taper pins, but you can improve on setscrews holding capability it you do it carefully.

I guess you'd call it "counter sinking" the screw into the barrel a bit.  I plan on putting tape on the drill bit so it won't mess up the threads in the sight base. That way just the tapered tip of the drill will stick out and drill a small indent for the screw to set into.  It really scares me to do it but I don't want that sight to move once I've sighted in. Also, with the set screw deal I  can always take off the sight and ream out the gas port if I run into feeding problems because of the ctg that I'll be using.  I'm building it up as a .300 Fireball/Whisper and hear tell that sometimes you don't get enough gas pressure from the stock set-up.

TNFrank:

I've got one of the YHM flip front sight/gas blocks on my SPR-type. First, it fits very snugly on the barrel as it is; I had to tap mine on with a dowel and brass hammer. Second, once you get everything aligned and the setscrews cranked down, undo them one at a time and Loctite the threads; this will give you extra insurance against any shifting or backing out.  As installed, this thing is ROCK solid and has remained so under live fire. If I ever do have issues, I will remove said screws and "dimple" the barrel as suggested. But as long as it ain't broke, I have no plans to "fix" it.

Well, got the kit. The front sight looks like it's stuck on the barrel pretty tight. I think I'll let it be for now, at least until I  find out how it  shoots. That way if I need to pull it off to ream the gas port it'll not be such a pain.   Yep, I like the folding sight, looks nice.  I'll be glad when I get the ARMS #40a and the Trijicon Reflex II on the rifle so I can sight it in. Talk to ya' later.

I have one that came with my Bushy modular carbine. It is separate from the gas block on mine. It clamps to the barrel over the gas block using four hex head screws. Very solid mounting arrangement once torqued and Loc-Tited. When I first shot this rifle, I noticed the front sight was slightly canted, which was easily corrected. Since I use an Eotech as my primary sight, the irons are normally folded down, and I periodically check them to the Eotech and the target. I give all the YHM products I've seen an A for quality. My only complaint is that their free float tube rails are not 1913 Picatinny spec. This can cause problems with some accessories that use a tight slip fit with no clamping rail (TD vertical grip).

The front sight post does seem to be alittle tight, I think I'll order a sight adjusting tool and a new front sight post, plus I'd like a set of M4 handguards too,  Looks like I'll be calling M1S and making a small order for some "extra" stuff, the wife will really love that.