Which upper+lower receivers for SPR? Colt or Northtech?

[Skyyr]

I'm building a "modernized" SPR with a Mk12 barrel. I've whittled down the receiver options between a Colt upper and lower receiver set and a Northtech Defense receiver set.

The Colt receivers are obviously the tried-and-true forged type. The Northtech receivers are billet.

I like the look of the Northtech set, but I've never really deviated from mil-spec parts in my builds (where applicable), so I'm a bit reluctant to switch to a billet set.

Other components are:


UBR stock
Geissele SD-E trigger
DD LPK
Geissele 15" Mk8 rail
AAC Blackout FH


I have no delusions of using this as anything other than a bench gun, maybe a hunting rifle, but I do prefer to keep everything mil-spec for reliability purposes when I can. I would never get a non/less-than-spec trigger, LPK, BCG, etc., but what about the upper and lower receivers? Any input on if I should lean towards one or the other?

[BillBond]

My vote would be for the Colt upper and lower.
That is all I use any more since I hate experimenting after getting screwed on LMT and Armalite crap.

[AM-15]

https://www.m4carbine.net/showthread.php?65306-Precision-Rifle-Semi-Auto-PICTURE-THREAD&p=2158522#post2158522

I was on the fence about installing a 4.5 lbs barrel on a standard upper.
Not anymore.
BCM4 upper which has a very snug barrel fit and an Anderson lower.
Above is link to pic's and component list that I updated today.
I know that this is my build and maybe not what you are looking for but it serves my bench shooting needs very well.

Clarence