300 piston upper

[HUNTER2]

Does anyone know of a company that makes a "piston" upper for 300 whisper? If someone does - would the blowback be the same as the GIS with a can attached? Have shot a few ar's but not that up on them.. was just never impressed with some of the crud coming back ....

[cav_scout_tj]

Does anyone know of a company that makes a "piston" upper for 300 whisper? If someone does - would the blowback be the same as the GIS with a can attached? Have shot a few ar's but not that up on them.. was just never impressed with some of the crud coming back ....

There are a couple pistol size piston systems. The PWS diablo is a good example:

http://www.primaryweapons.com/store/pc/viewPrd.asp?idcategory=11&idproduct=87

Most piston systems vent at the end actual piston stroke. So gas would be there, usually out in front, and no blow back in your face.

Now has anyone done this on a 300? Not sure. Mine does get real dirty fast shooting with a can.

CMMG also makes a nice piston kit, pistol length may come out soon.

[HUNTER2]

Will look into it.....Thanks for the info..

[HUNTER2]

Checked it out! Going to have to save some more..They really like them!!!

[Garrett]

Most piston systems vent at the end actual piston stroke. So gas would be there, usually out in front, and no blow back in your face.
Keep in mind, by all reports venting at the gas block also creates more noise as well. So while that won't be an issue for those who are shooting unsuppressed, the suppressor crowd might need to assess their priorities. Namely, do they want a quieter gun that has to be cleaned more often. Or the other way around?

[amafrank]

I can speak from experience on the piston types being a bit noisy. I have a SIG 552 in 300-221 with a 9" barrel. Its definitely louder than my friends contender with an 8" barrel even when swapping the suppressor from one to the other. However, I'd say that the standard AR types are also pretty loud compared to the single shots. They are still venting gas and even closer to the shooters ear so the noise level is higher at least to the shooter. In any case the piston types may give you a bit more energy to work with for operating the action. Face it, in subsonic land there just isn't much gas energy to work with but by using a larger diameter piston we can use the energy available more efficiently. If someone is offering a piston upper that can be fiddled with for such things as gasport dia, piston diameter etc its worth screwing with, at least to those who like the AR's. I'll stick with the SIG I think....

Frank

[dflicker]

I have a 12" piston upper built by LWRCI with a 4-position gas port and lightweight carrier. This is a one-off design but if there is enough interest it could go into production. I am currently using only two positions, off and subsonic-suppressed. Blowback with a suppressor is negligible. I'm waiting on an AAC SCAR-H can, the one I'm using now is a small 30 cal. Jet by MGSS which is pretty much useless. Essentially an oversized flash suppressor.

When the guys in the shop tested it with a full size (308) can, the first time they fired it they thought it was a dud until the bullet hit the target. There was a video of this on the LWRCI forum at one time but I think it's been taken down. It was quite funny seeing the expression on their faces.

[JFettig]

I am testing my Tok piston system tomorrow, if it works for that, I don't see why it wouldn't work for a whisper. It has a 4 position gas block currently. The only problem is that the only handguards it'll fit under are big M4 handguards like glacier guards(slightly modified), its 1.04" from the center of the barrel to the top.

If this works, I'll be testing it on the whisper next, it'll just take a new op-rod and no handguards.
I can imagine however that it might need significant work from this prototype.

edit- failure. needs redesign.

Jon

[Colohunter]

Ruger is coming out with a piston AR. Looking at the review on gunblast it has an adjustable piston with off, low, regular and high gas settings. Might be adaptable to the Whisper.

[Fudmottin]

This seems like a reasonable place to ask the question. Do AR piston systems work like on the FAL where you have an adjustment valve that vents to atmosphere?

Since the OP is interested in avoiding blowback of crud from a suppressor, does a piston system actually help with this? I would expect crud doesn't like to make right angle turns.

Finally, is there any real evidence that the piston design is more reliable than direct impingement? I'm sure it is cleaner for the action. But the usual reliability debates between ARs and AKs point at the gas system and heavy bolt without bothering to look at the fact that the 7.62x39 case has quite a bit of taper vs a straight wall that is longer.

Wouldn't a standard AR chambered in 7.62x39 be just as reliable as an AK? Have any MTBF tests been done?

The shorter case on the 300-221 should mitigate the problems that fouling cause.

[redtazdog]

When shooting with a can the piston and the gas upper both get
very dirty because the blowback crap comes from the barrel not the bolt/gas tube.
The action noise is the same with both piston and gas upper when using a can.
The gas uppers are quieter because they dont spit more noise out of the
gas block like a piston upper.
The only thing i have found to be better about the piston upper is it
does stay cleaner in the action when not using a can.