Planning my 10mm upper build here.
I want to use a standard Magpul handguard no fancy free float rail system or the like.
Pretty sure I am going to stick with iron sights but want the option to put a red dot on without a fixed front sight base.
So my thoughts are standard old delta ring in the rear. But up front install a YHM folding front sightbase, or equivalent that may be better.
https://www.brownells.com/rifl...sight-prod21446.aspx
Since there is no gas tube to keep the front hand guard cap from rotating I figured I would tap the gas tube hole in the front sight and use a small bolt to hold the front cap to the front sight.

Is there something flawed in my logic or a better way to go about such a venture?

After I typed the bit below, I remembered my 22 upper. I don't have anything holding it. Just the pressure of the D ring spring pushing the guard forward into the sight tower. I just pulled it apart to double check.


You could just use an old gas tube. Buy a cheap carbine one and cut it off short. Then you wouldn't be ruining the gas block if you ever change your mind and part it out or repurpose it.

Or just pin in some sort of rod or tube.

Black, what you are suggesting is exactly what PSA did with my 9mm upper. There's an allen head screw tapped into the gas tube hole on the FSB holding the handguard cap in place. Works just fine.

I have that very same front sight base for my ar. I took it off because it’s a pain in the ass to get it on perfectly straight, other than that it seems like a quality part. Plus with a standard front sight gas block I figure I could drop it and not worry about possibly losing my zero

Yeah, PSA did the same on my faux dissipator upper. Just a screw holding the front cap to the FSB. Works well enough and looks like any other install.
I personally like the idea of a cheap/used gas tube to hold it in place, especially on something as nice as the folding front sight you were talking about. Allows you to change your mind without risking your investment.

It's been many years, but I don't remember any issues. I might have used the laser bore sighter to set it up.



I used that sight because this was supposed to be used with a scope most of the time. As it turned out it never got used with a scope, so I turned it into an "irons" match rifle, putting an extended sight tower on it.