I do not have an AR in 5.56, I know I'm late to the game for this caliber. But after the Oct. 7 incident and the masses of illegals pouring into this country, I should have at least one AR in this ubiquitous caliber. I need to start stacking 5.56 ASAP as well. But I decided to build this AR as I have certain qualities I prefer and it allows me to have the attributes I want from the start.
Most 5.56 AR barrels are 1/7 twist of which I've owned in the past and have never been impressed when using the lighter bullets. They performed well using the heavier bullets like 69gr and 77gr, but those are considerably more expensive, especially when you want to stack deep. So, for shooting the lighter weight more affordable/available 55gr. and 62gr. bullets, I'm going with a 1/9 twist.
I don't want to get into the SBR world, I considered going in the opposite direction and thought really hard about going with a 20" bbl for more velocity, but reason prevailed and I'm going with a 16" bbl. I figured if the frontline guys can get it done with 14.5" or 10.5" bbls, a 16" bbl can certainly get it done.
It will be mid-length gas port and chrome lined and am buying from Del-Ton. I'm going with a standard A2 flash hider and a MOE SL handguard, I feel they're lighter than the aluminum free-float handguards and as durable. I'll be using a fixed front sight gas block from DEZ Tactical as the barrel is not drilled for sight pins. I have a BCG from Palmetto State and a slick sided flat-top upper from Spike's Tactical.
I'm getting the lower from PSA with MOE furniture and their nickel boron 2-stage trigger. I use the latch-less charging handles from Strike Industries and the ratchet castle nut end-plate with QD attach point.
It has a A.R.M.S 40L folding rear sight, a Primary Arms micro red dot on a QD mount and a 3x magnifier on flip-to-side QD mount.
I know this is not a spectacular build considering the high-end builds available today, but I want to keep it as simple and clean and light as possible.

Sounds good to me, only thing i'd suggest changing is that Del-ton barrel, and go with an FN CHF barrel with a pinned A2 front sight/gas block. User here "hochimin" sells a lot of Spike's stuff and often has a Spike's/FN barrel with the A2 sight and a delta ring assembly already installed, makes for an easy build, it's worth messaging him to see if he has one.

Slick side uppers are alright, I have one on a pistol build, but if it were my only AR i'd want a standard model with a port-door and FA.

Those Magpul SL handguards are the bomb, they extend farther than regular handguards too, the midlength is almost as long as a conventional rifle length. Love 'em.

@Molon will be along shortly to scold you for thinking a 1:7 can’t shoot lighter ammo properly. I’d go 1:8 or 1:7 so that you have the option of shooting the heavy stuff if necessary.

I have a 1:7 14.5” bbl that shoots 40gr vmax’s well.

I get that a FN CHF barrel would probably be a better barrel than Del-Ton's, I could almost buy 3 Del-Tons for 1 of those though. Also the Del-Ton is the lightweight profile. What I don't understand is why the assembled barrels use the triangular handguard caps, who uses those anymore?

I have a few 1:7's and all shoot my 55 grain handloads into little clusters.

More than one builder, i've had to swap out a bunch when i've bought assembled uppers.

ETA: The Spike's FN barrels I mentioned, you can get in a very slim profile, plenty lightweight and well balanced.

ETA2: All my rifles have 1:7 twist, and they shoot 55 gr and 62 gr really well, never tried 'em with anything heavier though, so don't know if they'd get even more accurate, but i'm very happy with them with the rounds I do shoot.

Well, the Del-Ton barrel was delivered today. I'm going to put it through it's paces and see how it performs. But first........I need ammo!

Triangle caps are std. for mid & rifle-length.  A mid-length with round cap is going to significantly limit handguard options.

OP already said he's using Magpul SL middys, they require a round front cap.

After the 10/7 invasion my thinking has changed greatly as far has having a few ar's around. All middies .all 1/7 .

Whole lotta people worldwide are re-thinking things these days.

Definitely this, just get an FN middy barrel if you can find one and run with it, its a quality piece you will not need to worry about for a very long time.

I have two of the Spikes/FN barrels and they are great, and the absolute last rifles I would ever part with.

The build turned out good so far, haven't had a chance to shoot yet, still need ammo. I could not get the castle nut off and broke one of my tools trying so no QD point there.
Since I have two 6.8 spc AR's that I use metal mags for, I decided to go strictly Magpul gen 2 mags for this build so I'll never confuse the mags/ammo.
Their nickel-boron two-stage trigger feels great and it's pretty light, should be a good shooter. I have a PSA nickel-boron BCG and 10 more Magpul gen 2 mags coming. Range report to follow.

Looks like a solid build!

Thank you Sir!

I built a 16" Franken using a light weight 1/9 DelTon barrel. I did get a chrome lined barrel and it took some rounds and some cleaning to get it to tighten up the groups.  I chose the 1/9 twist barrel for the 50, 52 and 55 grain bullets. I have not been disappointed.  It just took a bit longer than I expected to get the accuracy to come out.  Plan on 75 or 100 rounds with some stiff cleaning after each range session then watch the groups close up.

kwg

Thanks for the heads up, looking forward to putting it through it's paces.

Due to the modularity of the AR platform and the multitude of sales, it's easy for the Black Rifle Disease to kick in and you'll discover yourself owning several differently configured AR's.  My first one was a bull-barreled varmint gun that was a heavy pig.  Second was an 18" mid length SPR-ish build.  The next was very M4-ish.  After I covered the bases with a heavy, mid, and lightweight build, I created variations of the themes.

If you plan to upgrade your barrel, build another complete upper versus replacing the barrel.  Then you can swap the upper and put your original on another lower.  Spare parts become the seeds for the next build.

It's funny you say that, I was fortunate enough to have several spare parts to use for the build and save a few coin. I have already changed out the MOE grips for 15 degree grips and pulled the camo tape from the metal parts as I didn't want to have corrosion problems in the future with moisture getting trapped under there. I finally have ammo inbound so the moment of truth is nearly at hand.
I have gone through many parts and configs on my 6.8 AR's but feel they're how I want them to be at this point. I have spare bolts and have gone from folding front sights to fixed where I can.
I still might get a 20" upper in the future just because.