I have been reading a lot of thoughts on this topic and have no experience with the Gas Piston systems. I currently own a direct impingement gas system but can't stand the amount of labor associated with keeping it clean and lubed.

Although, looking at the Gas Piston systems I can't say the price is worth the minimization of cleaning. I know there are claims that GP reduces wear and tear and improves second shot accuracy.

What do you guys think. Are they worth the money?

Also there are conversion kits and entire uppers designed to work together. Any preference for one over the other? Any particular brand that stands out over the others?

I know a few years ago the GP systems had some problems with free floating rail forends. That seems to have been resolved. Or have I missed something there?

In 27 years of using the M16/M4 series I have never had to spend more than 30 minutes cleaning it. Even running blanks through it which is probably as dirty as it can get doesnt take long if you know what your doing. There is no need for dental picks except for trying to White Towel clean the weapon. "White Towel" or "IG Inspection" cleaning causes more damage from ham fisted Joes trying to dissassemble the trigger units and Losing parts or incorrectly reassembling them, or using sharp tools to gouge the upper receiver and chamber area, which eventually causes more corrosion.

RBC or Hoppes followed by elbow grease and a Issue Cleaning kit, lube with CLP or Mili-tech,Tetra job done.

Now the Gas Piston does have 1 benefit few know

The Bolt Carrier stays at a lower temperature due to the gases not being vented into its key. With Direct Inpingment eventually the Steel bolt will slightly expand from the heat of the vented Gases and in some Aluminum upper receivers will cause function issues.

Of course the amount of rounds you have to put out the spout for that is more than a Civvie AR shooter would typically shoot.

I would try AR-15.com boards if you want to get into the weeds of DI vs. GP operation.

floresh......... Linedoggie just about summed it up for ya.

quote:

Originally posted by m551sheridan:
floresh......... Linedoggie just about summed it up for ya.

Thanks guys. I was doing further reading and stumbled upon this:

-http://www.armalite.com/images/Tech%20Notes/Tech%20Note%2054,%20Gas%20vs%20Op%20Rod%20Drive,%20020815.pdf

I was under the impression that the GP system improved accuracy. But the above document from Armalite seems to contradict that. Obviously, Armalight has financial stake in the game and the document is a bit dated.

Seems for me the difference between the two is roughly $271. Not that significant. Of course I am looking at the CMMG conversion kit.

My main concern at this point is spare parts. There are conversion kits available but the individual parts don't seem to be available. Like the piston for example. Does one have to purchase the entire conversion kit just to obtain the piston?

Well as to Accuracy, just look at the Service Rifle Matches.

Most are now done with AR-15 series rifles over the Old M1, M14/M1A, and the odd M1903 shooter. If they're good enough for the National Matches and Presidents Hundred Match, National Infantry Trophy Team , they're good enough for me.

XXXhttp://www.odcmp.com/Competitions/M16.htmXXX
XXXhttp://www.odcmp.com/Competitions/Rulebook.pdfXXX

quote:

Originally posted by LineDoggie:
Well as to Accuracy, just look at the Service Rifle Matches.

Most are now done with AR-15 series rifles over the Old M1, M14/M1A, and the odd M1903 shooter. If they're good enough for the National Matches and Presidents Hundred Match, National Infantry Trophy Team , they're good enough for me.

I think it would make a better case if an organization that allowed both resulted in match shooters selecting one or the other. The fact that GP hasn't been widely adopted by the military is definitely a pro in favor of the DI side. Most especially as we have been fighting two wars with the weapon in question over the last 8 years. I would have to guess it is either because they haven't gotten around to testing one over the other or because they have and found it to not be worth the cost.

.308 firing Weapon which uses push-rod and piston system. After 1000s of rounds, no carbon in the receiver area. :

(cut and paste) http://www.pof-usa.com/p308/P-308-20-MRR-CF-308-SPR-C.R.O.S..htm



Would love to have one!!!

How it works:

quote:

Originally posted by greywolfghost:

Nice..

Now that has soom interesting technical features

The Fluted Barrel for one

Lightens the barrel
stiffens the barrel
gives more surface area for cooling

The large heat sink by the chamber

of course for a Semi-Auto they are largely superflous as you arent firing a basic load in 10 minutes, though the fluting would still help with barrel harmonics.