Discussion in 'AR Talk' started by thisismyusername, Jun 3, 2009.
BCM Bolt Carrier Group MPI Auto M16
And they are still there... Nice to see things are calming down a bit
just bought one.
Good to see, I missed out on the last batch.
Just got a LMT BCG on a notice from Ranier, so all is good.
out of stock
Back in stock...
man!! i've missed that three times! even with the email notification.
Why does it say (auto) I noticed they have a (semi) on their website.
Does it have all components in it or do I still need to buy firing pin extracted etc?
auto BCG are supposed to be more reliable than semi BCGs, bolt alone doesnt make it automatic
The auto is an M-16 bolt carrier while the semi is the AR-15. The auto is preferred in the carbine variants do to the faster cyclic rate of the carbine gas system (the auto carrier is heavier). The higher pressure= faster cyclic which is harder on the bolt and may reduce reliability. The faster unlock time in the bolt causes increased centrifugal force on the extractor which could cause the extractor to slip off the case rim.
Several things can be done to avoid this. A stronger extractor spring, auto carrier to increase the mass that is moved which will slow down the cyclic speed and heavier buffers.
No (before you ask) it is not illegal to install an auto carrier in a semi auto rifle.
BTW: the bolt is exactly the same, the carrier is different.
Hope this helps!
The FA carrier does not make a AR15 any more reliable - its just heaver. and closer to/may be milspec which gives it cool points
Excellent answer! That pretty much summed it up.....Oh by the way I was able to get one......"She-she-sshhaa" It will go well with my BCM middy......
Bolt carriers: a horse of a different weight | Guns Magazine | Find Articles at BNET
Love the lower I have that one. Waiting for a RRA LPK to come in stock somewhere and the money to buy it.
And that laser engraved BCG has me thinking. BF (best friend since no one else can figure it out) is a manager at a engraving shop. Now if I can figure out what I want to put on there.
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