Upper receiver for SPR build?

[Rogue556]

Ok guys, I am in the beginning stages of building an 18" SPR style rifle and I am trying to decide on what upper would fill the roll best. My plan is to buy either the Colt 6920 OEM/OEM2 or the BCM OEM (from Brownells) as the starting point for the build, and selling the barrel to recoup costs or just adding it to the spare parts bin. I currently own Colt and BCM rifles and both brands have served me well so I am pretty set on these as my choices. I have decided to go with either a Douglas barrel from HCS, or an 18" equivalent from V7 Weapon Systems. Rail will be a Geissele MK8. I have heard the BCM uppers themselves have a very tight fit as far as barrels go. If this is true, could the BCM upper provide slightly better accuracy? The Colt is roughly $270 cheaper than the BCM, so if there isn't a significant difference in accuracy potential I could put that money toward a Geissele trigger for the build.

What do you guys think would be the best starting point?

Thanks!

[msigette]

just out of curiosity why not just buy a Bravo Company 18" upper complete?

[Tx_Aggie]

If you're going to spring for a Douglas barrel from High Caliber then (to me) it's worth it to use something along the lines of a VLTOR MUR. Or better yet, spend a little extra to have High Caliber build the upper for you using their barrel, a MUR, and the Geissele Mk8.

[titsonritz]

If you're going to spring for a Douglas barrel from High Caliber then (to me) it's worth it to use something along the lines of a VLTOR MUR.

I am building a RECCE and this is the route I'm going.

[cougar_guy04]

Can't speak as to what is "best", but my SPR is built with a Krieger barrel and a "blem" BCM upper. That combination is good for MOA at 100 meters with Federal GMM and has gotten me solid hits out to 725. When assembling everything, the BCM upper didn't seem exceptionally tight for the barrel to slide into. Everything slipped/threaded together very easily.

I'd probably throw down for whatever you want, be it a standard Colt/BCM or MUR.

[dmd08]

My choice was Vltor MUR1A, Geissele mk4 15" and 20" WOA SDM. The barrel fit was just right. No wiggle at all. Didn't have to man handle it in. Upper fit is very tight with the San Tan lower and a couple other forged lowers I tried it on.

[Rogue556]

just out of curiosity why not just buy a Bravo Company 18" upper complete?

I had thought about a BCM barrel, but I am wanting to use a 1/7 for this particular rifle so it ruled the BCM out.

If you're going to spring for a Douglas barrel from High Caliber then (to me) it's worth it to use something along the lines of a VLTOR MUR. Or better yet, spend a little extra to have High Caliber build the upper for you using their barrel, a MUR, and the Geissele Mk8.

That's a good point, and I had forgotten about the MUR. That may be the route I take then, especially if I was going to spend the cash on buying a complete upper, I may as well just peice the upper together.

[Fatorangecat]

I bought a 6920 and replaced components. By the time I had finished the only OEM Colt parts left were the upper, upper parts kit, lower, and BCG. I was able to sell the Colt OEM parts and get my money back but I could have built the same gun on a different brand lower for the same money if not a little less. The Colt upper was not a tight fit on a WOA barrel but with the Colt upper, WOA barrel, SLR gas block, and MK8 I still get anywhere from .6 to 1moa 5 shot groups at 100 yards with BH 77gr on a typical trip to the range. If I had not already cerakoted everything I would have replaced the upper with a MUR1A.

[bp7178]

My SPR upper has a MUR on it now, and if I had to do it again I would go a different route. The forward assist block will prevent you from running 45 offset irons. Other than that, no real complaints. They tend to be logo'd up too much for my liking, but that's not really an issue if you are going to Cerakote it.

[Antonio5005]

I just bought a 6920oem2 the other day and will be picking it up today for an SBR build I'm doing. Same idea, sell the barrel and get a short one. As far as an SPR and accuracy goes, how does the fit between the the barrel and upper receiver have anything to do with accuracy? I could understand the bolt to barrel extension fit being something that could make a slight difference but not barrel to upper receiver. I figure once the barrel is tightened down that's it. No escaping gasses and any poi shift could be offset by the optic. It's possible I'm misunderstanding something though. Just don't see how it could affect the accuracy. Here to learn, I'll be doing an SPR also...