Pushrod or Impingement?

[ray1970]

With a properly tuned DI system, my carriers stay very clean as well...

Well, no matter how "properly tuned" mine are powder residue still seems to find its way in there. Almost like it's just part of the way a DI system is supposed to function. Go figure.

[MarkCO]

Yes, they are going to get a bit more fouling than a piston. I found a little faster powder to make sure that the powder is all burned before it gets to the gas port helps a good deal. Use slow powder like Varget, it will be a mess.

[ray1970]

Yes, they are going to get a bit more fouling than a piston. I found a little faster powder to make sure that the powder is all burned before it gets to the gas port helps a good deal. Use slow powder like Varget, it will be a mess.

I agree. Choosing the right powder probably makes the biggest difference in how clean the DI system runs. Personally, I've had good results with H335. Admittedly, I haven't tried everything out there. Is there one you prefer that runs really clean?

[275RLTW]

With a properly tuned DI system, my carriers stay very clean as well...

my "off the shelf" pistons do that with any ammo or powder...

[MarkCO]

X-Terminator and AA1680.

[BPTactical]

If the AR was supposed to have a piston, Stoner would have designed it as such. He did design a piston rifle the AR 18 which actually is a great little rifle.

To me, the piston is a hardware fix for a software problem. The biggest selling point is a cleaner bolt/carrier.
Face it, how many really enjoy cleaning a nasty bolt and carrier?

IMO a piston adds components that can fail/malfunction, mechanical complexity, weight forward on a barrel and cost.
Parts left off cost nothing, parts left off cannot fail.

[ray1970]

Face it, how many really enjoy cleaning a nasty bolt and carrier?

Maybe I'm just a bit masochistic.

[earplug]

Using the few powders and bullet combinations I have used as a comparison, I'd say the issue was very small. Powders have more effect then operating system.

[Great-Kazoo]

Maybe I'm just a bit masocheesit.

[BPTactical]

I see what you did there.....