Swiss SIG 553 pistols have hit the US market

[scubadds]

I use AAC sdn6
I have the 4 position gas valve
Have not shot it much. But seems to work just fine.

[freeride1]

4 position gas valve is great.

Wonderful host with for my Saker

[68ar15]

I got the 4 position valve for mine and the 0.9 mm port under functions just a bit with my surefire 6.8 can. Probably would work better with a 5.56 bore can. What I don't like is the off setting. It's only usefulness I can think of is for subsonic loads and who does that in 5.56? It looks like it could get inadvertently placed in the off position rendering it a single shot at the worst time. I'm tempted to drill a 1 mm hole in that position.

[freeride1]

I got the 4 position valve for mine and the 0.9 mm port under functions just a bit with my surefire 6.8 can. Probably would work better with a 5.56 bore can. What I don't like is the off setting. It's only usefulness I can think of is for subsonic loads and who does that in 5.56? It looks like it could get inadvertently placed in the off position rendering it a single shot at the worst time. I'm tempted to drill a 1 mm hole in that position.

It's for Grenade Launching. I assume you don't do much of that?

[Bret]

Does anyone know if the 4 position valve is compatible with the Sig 556?

[JoshNC]

Does anyone know if the 4 position valve is compatible with the Sig 556?

552 and 553 share the same valve. The 550, 551, and 556 share the same valve. The 552/553 valve is not compatible with the 550/551/556.

For more detailed info, take a look at this:

https://www.m4carbine.net/showthread...a-photo-detail

The photos are gone, unfortunately. If you email me through the board I can send you a pdf copy with the photos.

[Bret]

Thanks. I'll let you know on the pictures. I'm going to call Sig and see if they have undrilled valves available. My 556 SBR runs like a champ, but it definitely cycles too much gas.

[68ar15]

It's for Grenade Launching. I assume you don't do much of that?

Oh! I wish I did. Sounds like fun

[Meta-Prometheus]

Does anyone know if the 4 position valve is compatible with the Sig 556?

552 and 553 share the same valve. The 550, 551, and 556 share the same valve. The 552/553 valve is not compatible with the 550/551/556.

For more detailed info, take a look at this:

https://www.m4carbine.net/showthread...a-photo-detail

The photos are gone, unfortunately. If you email me through the board I can send you a pdf copy with the photos.

Thanks. I'll let you know on the pictures. I'm going to call Sig and see if they have undrilled valves available. My 556 SBR runs like a champ, but it definitely cycles too much gas.

I seem to remember somebody selling a 4 position gas valve on GB that would machine it to work with the 551/556 if the buyer chose to. I think it was Estes Adams, but don't quote me on that. Regardless, as JoshNC said the 4 position gas valve as is works only with the 552/553.

JoshNC, correct me if I'm wrong but I believe the 551/556 gas valves could also be modified to have extra gas positions added with machining? I don't remember specifically.

[eodinert]

Anybody know where there are any 553 diopter models lurking about? I'm having an urge.