I ordered a 16.1" Daniel Defense Recon Barrel from Rainer Arms on Friday, and it arrived today.

Barrel:
http://www.rainierarms.com/?page=shop/detail&product_id=1495

I now need to have the barrel sent someone to get the FSB pinned. I know I can send it to Adco, but what other options are there? Also, the barrel has M4 feed ramps. I'll get an upper with M4 feed ramps, but I don't know too many specifics about them. Are the feed ramps pretty standardized across brands? I recall hearing that there were differences, such as Noveske's being rather steep. Should I get a Daniel Defense upper for best match with the feed ramps? What other brands of uppers could I be considering?

I've never heard/read a single bad thing about ADCO, that is where I would send it.

I just got the same barrel in Saturday but luckily I don't have to have anything pinned on mine.

I'm putting mine on a Larue Stealth Billet upper with M4 feed ramps and they look to match perfect.

I think any of the M4 uppers will be just fine as far as the feed ramps go, I haven't seen much difference in any of them.

Ok, so my plan now is to get a quality upper if the Daniel Defense uppers don't come in before I need one.

Here's my build so far, give me any recommendations
Lower: (finished)
RRA Lower
RRA LPK
BCM MilSpec RE
Magpul CTR
CS Buffer Spring
H-Buffer
Magpul Trigger Guard
Hogue Grip

Upper:
TBD A4 Upper
Daniel Defense 16.1" Mid-Length Recon Barrel
LaRue 9.0" Handguard
Young Mfg Chrome M16 BCG
Troy Rear BUIS