I would like to build a military grade M-4 copy. I am thinking of using the below listed parts and a RRA lower. RRA Lowers fit tightly and I don’t like the sloppy upper/lower fit. That is the only reason that I’m using them.
BCM 16in, 1-7 Twist, M-4 Upper
RRA LPK
CMT or LMT BCG
CMT Collapsable Buttstock
H-2 or H-3 Buffer
Any opinions to the contrary, or am I headed in the right direction?
Looks like a solid and dependable build to me.
Nothing bad about your choices, but I prefer LMT parts to CMT, and a LMT upper would probably be quicker to acquire than a BCM upper, unless you already have one.
Looks like a good build. I would add a BUIS.
True, the BUIS, Optics, sling, and other extras will come along. Right now, I’m just trying to create a solid weapon for work and play. I wouldn’t mind using the LMT upper, however they mark their uppers as well as the lower and I already have the lower. I don’t the agency I work for will like mutt guns. They are kind of narrow minded.
The good thing about my agency, they aren’t knowledgeable about weapons, so without the external markings, I think I can still use it for work purposes…
Ram is right, the BCM uppers are going to be awhile. If they don’t like Mutt guns then buy an LMT lower too and use the lower you have for your next build 
xxxxx
Given your circumstances I would advise you to sell the RRA lower and get LMT parts.
Agree. An LMT lower with LMT LPK is superior to RRA IMHO.
As other have stated, BCM is a no go for awhile (read many months). Go with LMT.
C4
Not being beligerant but, as you know I have an RRA and ineviatbley(sp) they get thrashed and I wonder why. So, what is your problem with RRA lowers specifically?
Thanks, Mike
RRA stripped lowers are fine I think. We are mainly talking about the internals.
I would NEVER buy a complete lower from RRA for several reason’s, but mainly because they use non mil-spece RE’s and to make matters worse, they loctite them on.
C4
Pretty sure the RR LPK and CMT LPKs are one in the same so you could save a buck or two there…
I’d see G&R for that new BC group Grant is putting together
Not that there was anything wrong with your choices at all…
You might ask whoever supplies your stripped upper and lower to pick you out
a matching set for fit and color…
If you have your heart set on RR…Brownells has a 10% off sale going on and they do carry the Rock River “Match” paired uppers and lowers…
The code to get the discount is… C1T
hth
My RE was not mil-spec but luckily it was not loctited and came right off. Replaced it with a CAA which is milspec. Have you seen problems with the 2 stage triggers like I have or just the regular GI type they use?
Thanks, Mike
The RRA two stage triggers tend to shoot out and become single stage triggers (this happened to mine). This is why you see a lot of companies (like ADCO) offer “fixes” for them.
C4
Grant,
I have a RRA 2-stage trigger- would mind explaining in detail how/why they “shoot out”? Also could you provide a good alternative in the same price range?
Thanks,
Dave
They basically become one, long single stage trigger.
There really aren’t any options that any better in that price range.
To the best of my knowledge, there are only two combat rated, two stage triggers. They are the KAC and the Geissele. Something to consider if your using your AR for home defense for duty.
C4
Geissele makes 3 different styles right- the service one is the one I would need correct?
They make a DM trigger and that is the one that I use. Any of them should serve you though.
C4
for $280…it better be the best on the market! Have you tried the Timmeny yet?