BCM "MK2" Uppers - RFI

[Mark D]

While browsing uppers at the BCM website, I noticed their "MK2" uppers:

"Featuring BCM’s Patent Pending MK2 Upper Receiver
This proprietary design offers enhanced rigidity over the USGI product. The increased rigidity limits barrel deflection which aids in consistency/accuracy. Less flex also reduces premature damage, wear, and failure of bolt lugs from misalignment. A gas expansion chamber is machined above the charging handle track, combined with dual vents machined at the rear (each side, above charging handle latch) help to redirect and vent gas away the shooters face."

https://bravocompanyusa.com/ar15-upper-receiver-groups/bcm-mk2-upper-receiver-groups/


This is new to me, but I don't follow the carbine world very closely. Does anybody have experience with the MK2 variation? Is it a significant upgrade?

[Wake27]

They’re pretty new on the market, not many reports out at the moment.


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[Duke]

https://youtu.be/HTBkyHr_bX4

[Medusa]

I just bought one as part of a complete upper, but the weapon isn’t assembled yet because I’m waiting on other parts, nor do I have other non mk2s to compare to. I did watch the mac vid referenced above the other day.

[Casual Friday]

I bought one when they released them for the same price as their non blem complete uppers. I never assembled it into anything though because they're not compatible with Geissele rails and I was going to use it along with my OD green Fed rail that I've had for over a year. I ended up selling it on Tacswap.com and made a few bucks because they were outta stock.

[rm06]

I have the Vltor MUR on a few rifles as my preferred upper because of the improved stiffness / reinforcements. These predate the Mk2 of course, I'd be interested in a comparison of the two, especially the supposed gas redirection or expansion chamber in the Mk2 for suppressed use. BCM isn't in the business of selling snake oil in my experience so I imagine there is some legitimacy to the claim.

[GJM]

So if someone was buying another .300 BLK complete upper from BCM, should they buy the new MK2 upper or the legacy one, and Keymod, MLOK or QRF?

[Casual Friday]

So if someone was buying another .300 BLK complete upper from BCM, should they buy the new MK2 upper or the legacy one, and Keymod, MLOK or QRF?

I don't see a reason not to go with the MK2 unless you want to use a rail that isn't compatible with it. I have large mitts. Their MCMR/KMR rails are almost too narrow in diameter. It feels like I'm c-clamping a pencil. I'd go with the QRF, but I'm a sucker for quad rails.

[Clusterfrack]

So if someone was buying another .300 BLK complete upper from BCM, should they buy the new MK2 upper or the legacy one, and Keymod, MLOK or QRF?

I don't think the Mk2 adds anything for a shorter barrel. I actually prefer Keymod to MLok. I know, it's going to get me killed in the streets, and only MLok is strong enough if you are Operator As Fuck.

[Wake27]

I don't think the Mk2 adds anything for a shorter barrel. I actually prefer Keymod to MLok. I know, it's going to get me killed in the streets, and only MLok is strong enough if you are Operator As Fuck.

Keymod? Definitely gettin kilt in da streetz. I only have one and its the original magnesium KMR for the wife's gun, which means light weight was the priority. Its also the HD gun, but my KAC is the driveway gun so the KMR should never actually go into da streetz.

Definitely MK2 and either MCMR or QRF. The nice thing is they all use the same mounting system so you could swap them out.

[Mark D]

https://youtu.be/HTBkyHr_bX4

Interesting video. It seems like a well-designed upgrade to the A2-style upper. But I'll probably stick with the basic version for now, just because it's so well vetted.

[Doc_Glock]

So if someone was buying another .300 BLK complete upper from BCM, should they buy the new MK2 upper or the legacy one, and Keymod, MLOK or QRF?


I have both keymod and MLOK. I wish my keymod stuff was MLOK, but not enough to retrofit anything.

[NickDrak]

So if someone was buying another .300 BLK complete upper from BCM, should they buy the new MK2 upper or the legacy one, and Keymod, MLOK or QRF?

Keymod is nearly dead. Nowhere near the aftermarket mount/accessory support for Keymod compared to MLOK. Plus Keymod looks like tiny penises.

[rob_s]

I would typically be inclined to dismiss something like this as snake oil at worst, minimal to indeterminate value at best, but since it’s coming from BCM an Paul I’m less likely to dismiss it.


That said, unless you’re shooting thousands of rounds a year and experienced enough to tell a difference, I don’t much see the point.

[GJM]

The MK2 complete uppers are the same price as the legacy ones. I just picked one up in .300 BLK with a MLOK handguard, because the non MK2 uppers were out of stock. They did have a legacy upper in QRF, but I wanted something thinner for going in the GR1. I will have a lower with a Law adapter, and hope it fits.

[Moshjath]

If rigidity is my goal, I’ll just stick with my LMT MRP.

[ST911]

I got a complete BCM with Mk2 upper about two weeks ago, this one: https://www.gandrtactical.com/BCM-MK2-RECCE-16-MCMR-15-MLOK-GOVT_p_825.html

Opened the box, mounted an optic, threw some lube on it, shot about 1000 rounds of different loads without issue. Nothing stands out attributable to the receiver yet. The gun is GTG. I'll stretch out the distance and round count in the coming weeks.


If rigidity is my goal, I’ll just stick with my LMT MRP.

Plenty of experience with the MRPs as running-around and DM guns, they are also GTG. Heavier.

[littlejerry]

Would love to hear if anyone has experience with suppressed usage and can notice any improvements with the Mk2

[rob_s]

Would love to hear if anyone has experience with suppressed usage and can notice any improvements with the Mk2

I imagine that most of what you’re going to get will be along the lines of “my k&n air filter added 10hp”.

[breakingtime91]

I have a mk2 upper with about 200 rounds, all good to go so far (which you would expect) anyone had more time on one?

[jh9]

Similar low round count. Not really a rifle guy. But since the thread was bumped...

One thing worth pointing out is that the shortened forward assist makes it a LOT easier for a lefty to get a decent open-palm on an ambi charging handle. If they were more frequently in stock, I'd be considering replacing all my uppers with a mk2 equivalent.