BCM spare assembled upper conundrum

[TheRifleman]

I came upon some parts a few months ago. A QRF 12, 14.5 BFH EL P&W to a SFMB, and a BCG. All BCM of course. Previous owner was clean and said it was at least 2,000 between the barrel and bolt. Not a big deal, especially for what I had considered to be spare parts.

Months down the line, the QRF was traded for a BNIB MCMR13, last night I thermally fit the just arrived blemished BCM upper to match the used "patina" of the barrel and BCG, and this morning I logged into my BCM account and started adding a cam pin, retaining pin, replacement extractor kit, and a firing pin into my cart to save for later.

And now I'm totally not thinking of asking my FFL to order me as assembled BCM lower with PNT and the SOPMOD Mod 0 stock. WTF is wrong with me here??? I just wanted a spare assembled upper for SHTF replacement emergencies only.

Oof. What would y'all do?

[BoilerUp]

I'd order a T2 for it.

[TheRifleman]

I'd order a T2 for it.

I placed an Aimpoint Duty on top of a Scalarworks 1.57 just for this purpose, [BD]

Probably also going to replace one of my Surefire mini scouts on a few rifles with the CD Rein 3.0 and use that Scout on this BCM.

[BoilerUp]

I sympathize as I've spent quite a bit of $$ ahead of my state's new AWB to completely build out any receivers I had laying around or otherwise complete any partial projects. One of my projects was to make a non-NFA copy of one of my favorite rifles, which is essentially a clone of a BCM 11.5" carbine (CQB 11 KMR-A). So, now I have pretty much the exact same rifle in a 16" version (RECCE 16 KMR-A). But, of course, having the rifle isn't enough, it (and my other projects) need optics, WMLs, slings, and other various upgrades.

BTW, as much as I love and respect BCM, I always clone their stuff as what I really like are their handguards, grips, and BCGs, plus their factory stuff is notoriously difficult to disassemble and I end up tinkering with just about everything so that is a put-off for me. Also, I've never quite convinced myself to buy one of their barrels; I have come close a few times but have seen enough, even if infrequent, dissatisfied customers to cause me to select alternatives.

[TheRifleman]

When I read an AAR of the classes that I have taken, will retake, or will be at soon that I have wanted to take and see just what has broken....well at first I thought meh, I'll just have with me bag of parts and tools, and a vice to attach to the hitch if need be. But now? I'm thinking screw all that and just having a spare rifle and if that one goes too, to also have this spare upper ready to go as well and diagnose/correct later on my own time on just what happened.

I see that Rooftop has the lower that I am interested in too. Ugh. I'd rather buy either a G47 or a G19 MOS instead. Maybe some other time.

[Stone]

Its all perfectly normal, remain calm and just let it happen! Bwhahahahaha! Some of us here have had a single tiny roll pin turn into a full rifle build out! When your in full addiction mode you will actually be thinking of your next build while you are still ordering parts for your current build!

[TheRifleman]

Oof. Get out of my head, you! I already added the BCM equivalent of the A5 kit to my cart as well, unless I can find a lower that already comes with it and has been staked at their plant. Definitely an OCD at play here.

[Joelski]

Shit... you clearly haven't experienced a rifle growing out of random parts like detents and springs! Unless you get used to having no spares, you will see this happen with alarming regularity. Some "practical" voice goes off, spouting something like "well, we have all this, it's only a barrel, rail, upper and lower receivers and grip and you'll have a whole 'nother rifle!" Get to it! [:D]

[singaa760]

I have both...I like the Aero’s fit to all my lowers more so than the BCM....but, like someone else said, the barrel will fit much tighter in the BCM, so much so in fact you’ll need a bit of grease and a heat gun to install the barrel on the 9apps (https://get-9apps.com/web/)

[TheRifleman]

I have both...I like the Aero’s fit to all my lowers more so than the BCM....but, like someone else said, the barrel will fit much tighter in the BCM, so much so in fact you’ll need a bit of grease and a heat gun to install the barrel on the BCM

Nah, no grease was needed. Just a heat gun and a rubber mallet which is the same for their MCMR free floats as well. I actually prefer tight uppers to first lap and then thermally fit.

And welcome to the site friend.

[Joelski]

I experienced that tightness on a Radian upper receiver d/t the cerakote. My solution was to make a flap wheel out of a dowel rod and emery cloth strip. Chuck it in the drill and give'r hell for a few seconds and you have an evenly done, coating-free mating surface.

[TheRifleman]

Based on my personal experiences, I'd rather have anodized as much as possible and have them avoid coating on any mounting surfaces as much as possible to prevent any stacking with tolerances.