big lumber 9 Posted December 6, 2009 Report Share Posted December 6, 2009 http://cmmginc.secure-mall.com/shop/index.php?shop=1&cat=29 is this a pretty good rifle? Quote Link to post Share on other sites
Bean.223 365 Posted December 6, 2009 Report Share Posted December 6, 2009 I dont know much about CMMG BUT that is a Adams Arms Piston system they are using, its the popular one right now for the manufacturers. Quote Link to post Share on other sites
big lumber 9 Posted December 6, 2009 Author Report Share Posted December 6, 2009 ok so its popular... but is it good? Quote Link to post Share on other sites
mollysman420 19 Posted December 6, 2009 Report Share Posted December 6, 2009 AR ergonomics with AK reliability. Grate rifle!! Quote Link to post Share on other sites
big lumber 9 Posted December 6, 2009 Author Report Share Posted December 6, 2009 yah i guess the only thing its missing would be the really loose tolerances.. Quote Link to post Share on other sites
Bean.223 365 Posted December 6, 2009 Report Share Posted December 6, 2009 ok so its popular... but is it good? Well my thinking is, if alot of manufacturers are using it, it must hold up pretty well....I have no personal experience with them . Quote Link to post Share on other sites
big lumber 9 Posted December 6, 2009 Author Report Share Posted December 6, 2009 i understand...i really do appreciate all of yalls input Quote Link to post Share on other sites
superA 289 Posted December 7, 2009 Report Share Posted December 7, 2009 Check out AR-15.com, they have a piston only section. Quote Link to post Share on other sites
KrisFox 69 Posted December 7, 2009 Report Share Posted December 7, 2009 ok so its popular... but is it good? Well my thinking is, if alot of manufacturers are using it, it must hold up pretty well....I have no personal experience with them . There are engineering issues with using a retrofit piston onto a DI AR. 1. The off axis force of the piston on the carrier forces the rear of the carrier down, if a special buffer tube is not used or the carrier lacks a generous bevel on the back it will result in abnormal wear and possible damage to the buffer tube. 2. The bolt no longer receives forward gas pressure that it gets from DI operation. It drags on the lugs of the barrel extension (Minor issue) However this delays and prevents the cam pin from unlocking at the proper time. It then collides with the inside of the upper receiver resulting in a gouge that grows deeper as more rounds are fired. To "fix" this a spring is added to the bolt tail inside the carrier and/or a special roller bearing cam pin are used to prevent damage to the upper receiver. So if you plan to use a piston system look forward to spending an additional $100 minimum (in addition to the $250 more a piston AR costs over DI) to extend the longevity of the firearm. If you want a piston 5.56 gun, buy an AK, XCR, SCAR or wait for the Masada to come out. If you want an AR that is easier to clean buy a DI AR for $250 less and just hose it out with carb/break cleaner before re-lubing it. If you want to spend $250 and get more reliability send your bolt carrier assembly and barrel extension out for DiamondBlack, have the inside of the upper coated in Teflon, buy a complete chrome silicon FCG and Buffer spring kit and a set of Stainless FCG parts. Piston conversions for AR's have been around since the 60's. It is a fad that crops up once in a while and fades when people realize it's not better it's just different and more expensive. Quote Link to post Share on other sites
Bean.223 365 Posted December 7, 2009 Report Share Posted December 7, 2009 Which is exactly why I decided against perusing the Osprey Defense retro fit kit, the EXACT symptoms you describe are happening with this one as well. http://gaspiston.com/ I have since decided to save up for a XCR. BUT I hadn't heard that much about the above mentioned Adams Arms Kit... Quote Link to post Share on other sites
Wakal 10 Posted December 8, 2009 Report Share Posted December 8, 2009 Messed with the Adams piston setup at the Fort Benning match this past weekend...think "FN" gas system. Seemed neat I got back this afternoon to find a shipment of M4 barrels and a CMMG piston kit. I'll build that kit up tomorrow and see how it works Alex Quote Link to post Share on other sites
Bean.223 365 Posted December 8, 2009 Report Share Posted December 8, 2009 Messed with the Adams piston setup at the Fort Benning match this past weekend...think "FN" gas system. Seemed neat I got back this afternoon to find a shipment of M4 barrels and a CMMG piston kit. I'll build that kit up tomorrow and see how it works Alex Sweet man! Give us a report!! Quote Link to post Share on other sites
Wakal 10 Posted December 9, 2009 Report Share Posted December 9, 2009 The CMMG kit is quite spiffy looking. No idea how it works, because I discovered today that I had to order a new mill bit so I could modify the LaRue carbine handguard to fit over the piston assembly before I could build it up. I bought the darn CMMG intending to mount it to my favorite 14.5" M4 type so the damn Surefire can won't blow crap back through the receiver Alex Quote Link to post Share on other sites
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