Short Stroke gas system

[usgn]

Understand the HK416, SCAR, LWRC are all using short stroke gas system in their designs. Basically Gas & Carbon get dissipated in the front side of the weapon,doesn’t foul up the chamber so that weapon can run longer with less maintenance. No heat transfer to the bolt thus reduce jam.
No heat erosion = No jamming of weapon (Reliability)

If that's the case, why the sudden trend of using short stroke gas system as compared to conventional direct impingement system (M16, M4)since it claimed to be much efficient cleaner system? By the way, short stroke design was already out in 1920s.....

Any comments?

 

[winnyfield]

You've already answered much of you question.

Nevertheless, afaik the current gas piston trend began when US Delta Force started looking for M4 fixes and HK came back with the 416, the center piece being the gas piston. Since then every AR15 maker and accessorizer have jumped onto the bandwagon (it's a very popular civilian rifle). In addition, the M4 has been much more widely issued amongst US troops, it's no longer exclusively SF. So its limitations have become more apparent.

If US DoD wants it, it's actually not a difficult fix. Armalite even had improved their design ~40yrs ago with the AR18.

Here's an example of the after market fix:

[ame="http://www.youtube.com/watch?v=CWN-x2wbsLw"]YouTube - OPS-416 Gas Piston Upgrade for AR-15 Carbine[/ame]

 

[Gremlin29]

The M4 was actually created for truck drivers and the like, the shorter barrel and collapsable stock were meant to allow the weapon to be more manageable in the confines of a vehicle. SF adopted the M4 for a variety of reasons.

The M4 was never meant to be a main battle rifle. The problems encountered with the M4 center around the shorter gas tube causing reliability issues. That's because the gasses in the barrel do not build up sufficient pressure before the bullet exits which then prevents the weapon from making a complete cycle.

A second problem in that the gasses are directed into the chamber by the gas tube, which of course can cause fouling. Not a problem if you keep your weapon clean like soldiers do. SF operators can not expect to have opportunity to field strip their weapons every day, by virtue of their mission so the need to keep the weapon clean is problematic.

The short stroke piston on the HK and others solves both problems because 1. gasses are NOT sent directly to the chamber and 2. less pressure is needed to operate the system so, shorter barrels can be used without sacrificing reliabillity.