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Durkin Tactical Franklin Armory
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Posted: 4/22/2013 8:19:41 PM EDT
Building a featherweight AR15. Getting a thin-profile barrel, Clark cf free-float handguard, Micor titanium FH, etc. Goal is to have the whole weapon - sling, optic, and loaded mag - under 5 lb.

Which would be a lighter solution for front irons: standard triangle FSB, or a carved-down FSB as gas block, with a 2" Magpul rail and DD04013 (Daniel Defense rail-mount fixed front sight) on the carbon fiber handguard? Has anyone done the math on this before?

I know the difference may be negligible, but Ounces Become Pounds, and especially way out toward the end of the barrel I don't want a single molecule weighing down the front of the weapon that isn't absolutely necessary.
Link Posted: 4/23/2013 5:37:38 PM EDT
'standard FSB (no bayo lug): 4.5 oz

Daniel Defense rail mounted front sight: 1.1 oz
shaved FSB as gas block: 1.3 oz
Magpul rail section and hardware:?? anyone know?
Link Posted: 4/23/2013 6:14:55 PM EDT
The real question you should be asking is will the Magpul rail section be on the same plane as the upper receiver. Cause if it isn't, you should stick with the standard gas block/front sight.
Link Posted: 4/25/2013 1:48:01 PM EDT
I realize it would be a pain to make sure the rail on the Clark cf handguard was coplanar with the upper. Hasn't stopped some folks from doing it, but it might be beyond my abilities.

Okay, so let's say I'm stuck with a plain ol' FSB. Anyone know what the lightest FSB on the market is?
Link Posted: 4/25/2013 1:50:17 PM EDT
If you're going for a "featherweight," why have a front sight at all?

Link Posted: 4/25/2013 7:10:49 PM EDT
If you're going for a "featherweight," why have a front sight at all?


See, to my mind, that's like asking, "why have a bolt at all?" Irons are just an essential part of the weapon. Plus I don't yet have a gazillion-dollar optic on it (just the PA micro dot), so backup is currently necessary in case of primary optic failure.

Update: there aren't very many FSBs for a .625 barrel diameter; PRI makes a folding front sight / gas block that weighs 4.9 oz. But it looks like a standard .625" FSB weighs 4.5, so currently that's the lightest I've found.
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