Any iron sighted AR that I'm going to fire more than a couple rounds out of, I want the sights mounted to the barrel. If the barrel heats up and should start to go this way or that way, it brings the sight with it and still shoots well no matter how hot.

I have only one iron sighted upper with rail mounted sights and it's for hunting, so no heating up.

I have four iron sighted uppers, one rail mount, three FSB... though one of them is an "it is but it isn't".  

I have them on all of my ARs. I use a Daniel Defense rear sight, and you could set a red dot between them if you like. It works well for me. Here is a link to the rear:

https://danieldefense.com/a1-5-fixed-rear-sight.html

I like them. I’m not a long handguard guy. I like lightweight, simple builds and it keeps me from buying a buis front. I sometimes mount a dot and the fsb doesn’t bother me at all.

I have both with and without. My current gun on a rifle rack in my closet sports a fsb and DD rear. Good sturdy combo.

As I have moved through my AR life I prefer simpler lighter guns. I rarely mount more than a light and an optic so fsb’s work for me.

I will not own an AR15 without a fixed FSB.

In all honesty my favorite rifles during my time with Uncle Sam has been my Colt M16A2E4 and the FN M16A4 with the adjustable stock and had iron sights.

It wasn't until I re-enlisted in 2009 that I really became an iron sight person. When I received that FN M16A4 with the iron sights I just clicked with. Between the iron sights and my Army Issued BCG's I began to love shooting prone unsupported at 300+ meters.

Maybe I am just institutionalized but I cannot see me owning a rifle without them.

Both my Colt HBAR and Bushmaster Carbine both have the fixed FSB. I've just been used to that style since the 70s and it works for me. I also have an AR which is a SBR in 9mm. It has a fold down sights and they're OK. It also has a rail for which my intention is to mount some sort of red dot sight on. That's why it does not have the fixed FSB.

Yep. Colt LE6920 Magpul that I converted a few months ago to long forend.

Who makes that rail?

quote:

Originally posted by tatortodd:
Yep. Colt LE6920 Magpul that I converted a few months ago to long forend.

quote:

Originally posted by SgtGold:
Who makes that rail?

It’s the UTG PRO AR-15 Super Slim M-LOK

I took this photo for a different conversation on colors, but it happens to be 3 of my FSB rifles.

I'm not a fan of scopes on FSB guns, unless it's something mounted to an A1/A2 setup.

I can think of two that have FSBs, my current HD carbine built on a 14.5 pinned Colt SOCOM barrel and a Larue 7” quad rail. The other is a mid-length 16” hbar built around a Larue 9” quad rail that wears a 4x Trijicon scope. The FSBs still work just fine. Everything newer than those builds have pinned lo profile gas blocks.

I have optics on the 5.56, but I like it a lot on the 9mm.

and of course if you don't like your pinned fsb its pretty easy to convert it to something that is still pinned for reliability but clears a new FF handquard barrel nut if that is the direction you are headed in. I've done a few in just a few minutes.