BCM blem uppers

**bobcatdriver** · 02-09-24, 13:39

Originally Posted by fedupflyer

Not in my experience. I purchased a couple of blems and they were both NOT tight in the barrel extension area. Two different barrels slide right in.
Purchased a "retail" one and had to thermally mate it.

Bought a couple more "retail" uppers and one would take the barrel extension about half way before I threw a heat gun too it.

I have bought several BCM uppers and I get mixed results with "tightness"
Starting to wonder about BCM QC.

Interesting. All four I've used have required the heat gun. Barrels were Colt, MMC, Spikes, and a Brownells.

**TAZ** · 02-09-24, 13:43

Originally Posted by bobcatdriver

Interesting. All four I've used have required the heat gun. Barrels were Colt, MMC, Spikes, and a Brownells.

Same here. Both builds required heat to the upper, and not hair dryer or heat gun heat either. More like a torch. Wish they had mk2 blems

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**markm** · 02-09-24, 14:39

Originally Posted by TAZ

Same here. Both builds required heat to the upper, and not hair dryer or heat gun heat either. More like a torch. Wish they had mk2 blems

I'm not digging that action.

**bobcatdriver** · 02-09-24, 15:22

Originally Posted by markm

I'm not digging that action.

Using heat? It won't hurt a thing when using a good heat gun. On the sotar site, I see he used mapp gas instead of propane. I don't like using a torch, the heat gun is easier to control.

**markm** · 02-09-24, 15:32

Originally Posted by bobcatdriver

Using heat? It won't hurt a thing when using a good heat gun. On the sotar site, I see he used mapp gas instead of propane. I don't like using a torch, the heat gun is easier to control.

Yeah. I don't even own a heat gun. Is any of the moly grease even still in between surfaces?

**rrich1** · 02-09-24, 16:30

I wanted to pick one up but they wont sell to IL even with le credentials. Picked up a fcd upper instead. Sucks because that pricing is great and would have probably got 2 even though I don't have another lower.

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**bobcatdriver** · 02-09-24, 19:10

Originally Posted by markm

Yeah. I don't even own a heat gun. Is any of the moly grease even still in between surfaces?

Took the upper with the spikes barrel apart after about a year of shooting, came apart fine after heating it up. Still a bit of moly residue. Went back together just as easy.

**Red*Lion** · 02-09-24, 22:26

BCM uppers are consistently tight and require a thermal fit.

**markm** · 02-10-24, 06:02

Originally Posted by bobcatdriver

Took the upper with the spikes barrel apart after about a year of shooting, came apart fine after heating it up. Still a bit of moly residue. Went back together just as easy.

Good to know. Thanks.