I have a PSA premium upper, FN barrel, non-hammer forged, not sure when they came out with these.  Never been a big fan of the old handguards and want a free-floated upper.  Worth doing it with the profile type and barrel, all my builds before have been from scratch?

What gas block should I get?  What rail length would be best?  Just start from scratch?  

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If you are gong to use an optic as primary it is always an advantage to free float, at least unless you plan on shooting free hand 100% and even then to a point.

I did a build with an upper very similar to yours where I cut and filed the front sight down to create a low profile gas block. The rifle did not shoot considerably tighter after the free float, but there is no worry about POI shift when resting the handguard on anything, so I can still see the merit. I would consider doing that first before spending money on a different gas block.

Mainly looking for rail space and not wanting to buy a complete upper or parts for a new one.  Barrel is fine, only 400 or so rounds down it.  Wanted to see before putting the effort in and buy a rail for it.  May try cutting down the A-frame first and give that a try.

9” BCM QRF and keep the FSB.  

I'd shave the sight post down personally. People like ALG rails for cheap, I've never owned one. BCM mlok rail or Midwest combat mlok would be where I started.

LaRue Quad, and keep the front sight.

Done it.


As mentioned, only saw the benefit when resting on something. Plus, get more rail space.

20210130_160209 by brandon hobock, on Flickr" />


Definitely

Google "free float fsb hand guard" you have enough bad ass options to keep the fsb.

Thanks all for the replies, definitely some great options to consider!

A winner.
That is nice, damn nice.
BRAVO

THIS.

Keep the FSB and run a free float.

Best Of BOTH world's!

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Any decent AR will shoot about 0.4 MOA. This one got a lucky Core15 CL barrel that can get in the low 3s. The UTG Pro FF rail it has is minimal; it can handle sling tension and preload, but don't beat on it too much. The lighter the barrel profile, the more important it is to float.

Longer rails with FSB cutouts are tits.

Thank you!

I prefer a relatively long handguard and a low profile gas block for all my builds. I primarily use red dots or magnified optics with QD mounts and backup iron sights. I prefer this so I can use a bipod, stubby vertical grip, a light if desired and the handguard is highly practical when the barrel is hot. It also allows you to slap the handguard on/against anything, any time without touching the barrel. I have no need for fixed front sights because they are just an obstruction of my view, an annoyance to me and serve no purpose 99.999% of the time.

Now if you will not be using an optic then you have at least three options. Go with a fixed front & rear sight with a short handguard. Go with a fixed front sight clamped on the end of your handguard (longer sight radius & benefits of a longer handguard) and a fixed rear sight. Folding front & rear sights for future option of using an optic.

After firing a number of rounds, obviously the barrel will be hot. It is extremely convenient to be able to lay it down, set it on/against something, grab the AR and/or hand it off to someone without having a highly limited amount of surface to hold on to.

IMO if you are going to shoot FMJ ammo don't waste your money or your time. Standard handguards won't hold you back shooting surplus ammo.

If you reload or want to push the limits of your barrels potential with Federal Gold Medal Match or similar premium ammo then a free float tube will help. Daniel Defense and Centurion Arms make excellent free float rails that you can attach to your GI barrel nut without disassembling your rifle.

GI front sight towers are the best gas blocks. Nothing comes close in strength. As long as you have a scope with more than 3.5X power you won't see the front sight tower.

I'm not a fan of long rails even though that's the trend nowadays. Anything longer than 12" is wasted on me. Centurion makes 12" free float rails that have cutouts for the front sight base on mid gassed rifles. That's about as long as I would go. A standard 9" (edited) will get you to the rear edge of the front sight base if you don't want a cutout.

9” on a midlength with a FSB.

If you will be shooting while rested on the handguard, as well as shooting without support, free floating will absolutely make a difference regardless of ammo.

Which is the whole reason for doing so.

I free-floated one of my PSA 10.5" Premium barrels using a Daniel Defense Omega quad rail.  I see they now make the Omega in both Key-Mold and M-Lok as well.  All three versions are available for carbine and mid-length gas systems.

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Samuse is correct. 10" partially covers a small gas block, an eleven inch completely covers a gas block.

The nine (9) inch rail gets you to the standard sight tower.