Just finished my 604 build after about 8 months:



Ended up just buying whatever parts I could to finish it after waiting so long.

LOWER
-Anderson lower and parts kit
-Aero precision rifle extension/spring/buffer
-Brownells Stock (Type D)
-Brownells A1 grip
-Brownells 20rd mag

UPPER
-KM Tactical slick side A1 upper
-1x9 twist no name stripped 20" lightweight fsb barrel from AR15discounts.com
- Brownells 3 prong and lock washer
- Brownells A1 handguards
- Brownells flat slip ring
- Brownells A1 front sight post/spring/detent
- Brownells A1 ejection port cover
- Brownells rifle length gas tube
- original Colt A1 rear sight parts from Retro Rifles
- Aero Precision standard charging handle
- Brownells slick side chrome full auto BCG
- Retro Rifles machined firing pin retainer
- new nylon OD sling
- misc manufactures front swivel, swivel rivet, slip ring spring/snap ring

Looking good!

Great build, and congrats! Be sure to let us know how she shoots

Will do!

Good job Amigo.  She's a beauty.  But then what slick side isn't.  If you're waiting for the proper lower to pop up, what you have there will certainly get you by till then.

From another Brownells, KM satisfied customer.  Love those USAF 20" AR's.

Very NICE build.  I'm another big fan of the 604!

This is my first retro build and compared to a m16a4 clone, the 604 is much lighter and nimble.

You know, looking at that rifle a bit more, I’m thinking is it really worth the effort to turn down the gas block on my Pencil barrels To use a .625 FSB.
I mean that looks good as is and the barrel portion under the FSB just not stand out.
I guess it’s just being a bit OCD. But I could think I could live with something like that.

Of course I’ll have to locate some non-F front sight bases.

Agreed on the lighter and nimble, going back and forth makes it feel even more so. Nice build, look forward to the AAR of warming it up!! My clone is my favorite to grab and plink with hands down.

Here is a picture of the barrel by itself, it's not very noticeable under the FSB