My mk114 Mod 2 has four ports on the bottom of the tube. See the chopsticks, these are the aft ports.
There are two smaller ports about 1.25" forward of this set
https://i.imgur.com/Gx4vxXD.jpg
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My mk114 Mod 2 has four ports on the bottom of the tube. See the chopsticks, these are the aft ports.
There are two smaller ports about 1.25" forward of this set
https://i.imgur.com/Gx4vxXD.jpg
The PWS system dumps the gas under the handguard. The handguard is easy to remove though, so cleaning is simple when it becomes necessary. There is an animation on PWS's homepage that shows the function well: https://www.primaryweapons.com/
MCX handguards remove with nothing more than the receiver take down pin.
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No, it and the LWRC vent in a very similar manner: once the piston moves back far enough to clear the spigot all the excess gas residue spews in a 360 degree fashion (the top of the barrel, the inner sides and top of the handguard/rail). The will also spew forward onto the gas block.
The LWRC does have one saving grace though, it's rail system has a removeable top/front portion which allows for relatively easy access to the residue areas.
Why would you design a system to blow gas residue directly down onto the barrel? Ruger does that too. Never understood that line of thinking. They couldn't think of a better way/place to blow it out?
To me, having played with enough piston systems over the years to make this observation, my preference would be for a system that expelled gas into the atmosphere forward (somehow) of any handguard/rail. Similar to the HK416 for example.
When I had an MCX I took off the handguard and made note of the little black dot where carbon deposited right above the gas exhaust port/piston. I had my buddy mill a hole in the top of the handguard so gas residue would blow right out that hole and not build up underneath the handguard. I have a pic of it in the MCX thread.
(second to the last post on the following page)
https://www.m4carbine.net/showthread...t-an-AR/page42
As with everything else in life, there are pros and cons with any solution. Venting towards the barrel builds a bit of carbon, but not nearly as much as I would have thought, even after several hundred rounds. Venting upwards through the handguard of the MCX, as in your solution, has its own downsides or Sig would have already implemented it. As does venting forward, as HK does.
Personally, I have no practical objection to PWS's solution. It does bug me that carbon is being deposited on top of the barrel simply because I don't like the idea of it. But in practice, the gas isn't really even that hot, and the carbon is easy enough to clean off every few cases of ammo.
Life is full of compromises, pick one.
Any idea how the Lewis Machine & Tool piston system vents?