BCM Blem uppers back in stock

[357Max]

They've been OOS for while. A little more $ than before, but still a bargain IMO. Just picked up 2.

BCM® Upper Receiver - M4 Flat Top (M4 Feedramps) Complete (Unassembled) - DEMO/Scratched

Fully Assembled, with round forward assist and ejection port cover, and T-Markings laser etched into receiver. This receiver has the M4 feedramps machined in.

bravocompanyusa.com

 

[PBWalsh]

See this post... checks checking account... add to cart.

Have nothing specific in mind either, probably a pistol build.

 

[bfoosh006]

Thank you for posting !!

 

[TxWelder35]

Thanks for the heads up!

 

[Jigstick]

The last few I purchased didn’t have a scratch on them. Good buy

 

[godofthunder]

The last few I purchased didn’t have a scratch on them. Good buy

The last one I bought was most definitely a blem, but I knew I would be coating it so I didn't care.

 

[PBWalsh]

Lol, I mean, it is technically a blemish. Not one I care about. My rifles get used, no safe queen ARs here.

Oh, these come with a full upper parts kit if you didn’t know, and a buncha stickers.

Should be built into a pistol after I buy another CZ handgun.

 

[TxWelder35]

Got mine yesterday, briefly looked at them through the package and couldn’t see a blem.

shocked how fast they shipped and arrived

 

[Hetzer]

I hadn't looked in a while. Got used to them being OOS. Thanks for the heads up!

 

[357Max]

Mine showed up today. Tiny blem on the side of 1 (you really have to look hard to see it) & the other I cant find a thing wrong with it........nada nothing.

 

[KZP]

Lol, I mean, it is technically a blemish. Not one I care about. My rifles get used, no safe queen ARs here. View attachment 7625325

Oh, these come with a full upper parts kit if you didn’t know, and a buncha stickers.

Should be built into a pistol after I buy another CZ handgun.

You are braver than I am. That upper is totally going to explode after a magazine or two.

 

[bfoosh006]

I bought some... I can't see any blemishes. I didn't go over it with a fine tooth comb... but just casually looked them over.

Each one came in a plastic bag, with the forward assist and ejection port parts in their own plastic bag, and a piece of paper commenting on a thermal fit is needed.

3 have the Star forge mark, one has Star and Square around it forge mark.

I tried inserting a barrel, inserted a BCG, threaded on a barrel nut, and attached each to an existing lower.

Out of the 4 Blemished Uppers only the Star and Square forged marked one would allow the barrel extension to be inserted ( tightly ) about a little less then 1/3 of the way in.

The fit on the Rainer Arms Ambi lower was loose enough to be easily installed and removed... but not sloppy fitting. So completely normal compared to my other OEM complete BCM uppers on that lower.

No issues otherwise ..what so ever.

I am half tempted to order more if they are still available !

I haven't tried lapping the upper receiver face yet.

 

[357Max]

Every upper I've ever lapped has taken some time to true in (VLTOR MUR, Aero M4E1 & std, BCM, & billet).
It's kind of surprising really given the capability of modern CNC + the fact it's well known this mating surface is important. They must machine that damn extension face in about .2 seconds. It should be dead nuts & I'm baffled as to why upper lapping jigs are even still relevant.

Well crap I just realized I'm going to have to make a 15"+ extension for my lapping tool for this

 

[bfoosh006]

Every upper I've ever lapped has taken some time to true in (VLTOR MUR, Aero M4E1 & std, BCM, & billet).
It's kind of surprising really given the capability of modern CNC + the fact it's well known this mating surface is important. They must machine that damn extension face in about .2 seconds. It should be dead nuts & I'm baffled as to why upper lapping jigs are even still relevant.

Well crap I just realized I'm going to have to make a 15"+ extension for my lapping tool for this

View attachment 7626520

After speaking with an anodizing rep, he did say the anodizing could be part of the issue. He told me anodizing is rarely a even , uniform thickness, and even the items position in the tank can produce different thickness.

 

[357Max]

After speaking with an anodizing rep, he did say the anodizing could be part of the issue. He told me anodizing is rarely a even , uniform thickness, and even the items position in the tank can produce different thickness.

Yep I've thought about the anodize being partly to blame & haven't completely ruled it out.

The one thing consistent with all the uppers I've lapped is that I'm lapping .001 - .002 bare aluminum on part of the mating surface before getting through the anodize on the rest. If it were just a variation in anodize thickness I should be lapping off the thick anodize portion & then hitting bare aluminum all the way around once through it. That's not what happens though.

Either the anodize process is causing a warp in the aluminum or it wasn't flat before anodize. I'm leaning towards the latter.

Left side of below pic (VLTOR MUR) you can see on the left side a few thousand's have been lapped off and the right side anodize just came off.
Brownel's lapping tool + fine compound was used.