So far, I've got a new DD 10.3" barrel in 300blk and a really funky looking lower with finger grooves on the magwell that I received as a gift. I may get a more standard lower later on. I plan on using a Thordsen buffer tube cover on a keyed carbine buffer tube I have.  
What parts from here on out would highly recommend me using (as in a specific upper, bolt, gas block, rail, muzzle device, etc...)

A suppressor may be in the future later down the road.

I like the Aeroprecision M4E1 Uppers w/ their handguards. It makes installing a barrel,handguard, and gas tube extremely easy. The diameter is i believe around 1.8 inches so suppressors can be fit into the HG. I have an SLR adjustable gas block with a Faxon lightweight BCG and it works really well; I like reduced weight. As far as muzzle device, go for anything that goes with the suppressor you might want later. AAC, silencerco, ect. I always prefer muzzle brakes over flash hiders

Thanks for those suggestions. I'll go and look'em up.

Working on slowly acquiring the components now for a 300 blk pistol with suppressor under the rail. I've decided on...

Spikes stripped lower (purchased 2 earlier with consecutive serial numbers)
Noveske or BCM stripped upper
SLR sentry adjustable gas block
Phase 5 pistol buffer tube
Noveske QD endplate
Odin works 12.5" hand guard
Rainer 7.5-8.5 bbl. SS -black (barrel manufacturer and size still up for debate)
MRO or RMR sight
Toolcraft bcg
Ergo grip
Suppressor Co Omega
ASR 3 prong flash hider

Cerakote lower, upper, rail, and buffer tube in white, patriot brown or burnt bronze. Leaning towards white just for the heck of it since our corporate colors are black/white.

If I weren't tucking the suppressor under the rail I'd be going with a SLR helix rail or Noveske Gen 3 upper and NSR rail, this I will save for building out the second spikes lower.

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