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4/7/2010 5:34:21 AM EDT
I have one on order. I am putting it on my Bushmaster lower. I would like to hear from people who HAVE one. Thanks!!
4/7/2010 5:55:23 AM EDT
[#1]
I have one of the early conversions with the aluminum gas block that has over 50,000 rounds full auto on it with no problems.

CMMG sent us one of the new models and we have been abusing the hell out of it as well.  The new one has about 20,000 full auto.  

The only problems we have had were a few broken extractors.  Not a fault of the piston.
4/7/2010 11:52:43 PM EDT
[#2]
Quoted:
I have one of the early conversions with the aluminum gas block that has over 50,000 rounds full auto on it with no problems.

CMMG sent us one of the new models and we have been abusing the hell out of it as well.  The new one has about 20,000 full auto.  

The only problems we have had were a few broken extractors.  Not a fault of the piston.


Did y'all replace the piston return spring the at the recommended 7500 rounds?
4/8/2010 2:33:29 AM EDT
[#3]
The only thig we have replaced in any of the uppers are a few extractors and a couple of barrels. We have shot out the barrels on full auto and the piston has not failed yet.
4/9/2010 2:11:11 PM EDT
[#4]
I have one, and I have only put about 400 rds through it, but it has performed just fine.  Luckily I live in central Missouri, and live just down the road from a guy that works at the factory assembling rifles.
4/12/2010 3:46:37 PM EDT
[#5]
I ran 160 rounds today on my CMMG upper/Bushmaster lower. It ran great with one round catching on the feed ramp. Overall I am very impressed with the setup.
4/13/2010 4:06:22 PM EDT
[#6]
Who has the CMMG piston uppers for sale?
4/13/2010 4:15:20 PM EDT
[#7]
run a google product search.  you'll find vendors selling them for around $640+
4/14/2010 8:29:01 AM EDT
[#8]
I don't have a lot of rounds through mine yet, but it has not failed me.  Of course, I have another CMMG upper which is DI and it has never failed me either!  I would recommend a CMMG gas piston upper to anyone.
4/14/2010 3:20:46 PM EDT
[#9]
Anyone know why CMMG pins the gas blocks on the piston guns rather than bolt them on? Can this become a problem? Thanks!
4/16/2010 1:15:55 PM EDT
[#10]
Quoted:
Anyone know why CMMG pins the gas blocks on the piston guns rather than bolt them on? Can this become a problem? Thanks!


They have the option of a clamp-on gas block as well.
4/16/2010 2:01:12 PM EDT
[#11]
I would assume to eliminate any chance of it walking. since you actually have something pushing against the gas block every time you pull the trigger.  I know osprey recommends that if you go with some of the low profile gas blocks that you should drill into the barrel a hair to make sure the screw rest to eliminate any chance of the gas blocking walking.
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