[MgoBlue]

I'll be joining the MPX owners club next week and have some questions for the experts. On my DI AR-15's I use adjustable gas blocks so my cases eject about 4 O' clock, whether I'm shooting suppressed or unsuppressed (almost never).

On videos of folks shooting the MPX whether suppressed or unsuppressed it seems a lot of them eject around 2 O' clock which means a higher than necessary bolt speed and greater chance of brass damage. I also want go absolutely minimize the gas/particle blowback on it since I'll be running it suppressed and am having my smith chop it to 4.5".

Sig markets the piston system to self adjust regardless of ammunition, is there any reason why they wouldn't have designed it to eject the brass farther back? Is it possible to change the spring in the piston to slow the bolt down?

I've never owned a piston AR so this may be a non issue compared to DI or blowback guns, what say you MPX owners?

 

[USMC6872]

guys.
You want to remember that the weapons we are talking about are designed for Conflict. The HK 91 I owned ejected at 2:00 and threw the brass into another zip code. My M-14 did the same. the reason is that you do NOT want brass to collect around a soldier/Sailor's feet and cause uncertain footing in combat. Hence you want it to go Forward and Far, Far away.
again. here is Civilian vs Military requirements. of a weapon.

 

[MgoBlue]

If I remember correctly there is no spring in the gas block for the piston.

I think it springs it so hard due to the mags when being full are super tight.

I know there's a lot of stuff online about mpx being super gassy but I've never had a problem with it and I even had my barrel/block opened up.

I did find a gas block cleaning vid and you're correct, no springs in that assembly. It appears the only way to slow it down would be to change the recoil springs though I'm unaware of any aftermarket springs that do that at this point.

 

[MgoBlue]

guys.
You want to remember that the weapons we are talking about are designed for Conflict. The HK 91 I owned ejected at 2:00 and threw the brass into another zip code. My M-14 did the same. the reason is that you do NOT want brass to collect around a soldier/Sailor's feet and cause uncertain footing in combat. Hence you want it to go Forward and Far, Far away.
again. here is Civilian vs Military requirements. of a weapon.

While I have not seen that in any Sig literature, it makes absolute sense. What I have read is that Sig designed it as a modern replacement for the MP5 (not going to touch that topic with a 10ft pole) and would definitely lend credence to your observations.