Swiss SIG 553 pistols have hit the US market

[Mike Miller]

Anyone know anywhere in the Southeast that I can rent a 551 or 553 to try one out before I put money down for a conversion kit and lower? From the last Facebook video, they should be coming soon

[PGT]

It's a smooth shooting 5.56 AK variant. Not sure what shooting one ahead of time will convince you of. Nice guns, but not nirvana or anything.

[Mike Miller]

I guess mostly the feel of one with a suppressor. I don't have a suppressor for my AK.

[PGT]

Well....then it gets into whether or not the gas regulator has been swapped for a 4-position. Here's a video of a buddy shooting my 553 and also another of my old US-made 551-A1 (in slo-mo....to show the overgassed nature of these).

[PGT]

[Bret]

Well....then it gets into whether or not the gas regulator has been swapped for a 4-position. Here's a video of a buddy shooting my 553 and also another of my old US-made 551-A1 (in slo-mo....to show the overgassed nature of these).

The 553R comes with a 4-position gas regulator. The 7.62x39 cartridge and 4-position gas regulator might make it a better option for a suppressor. BTW, while the Swiss 4-position gas regulator will insert in a US rifle, it not work as-is because the cup is too small for the US gas piston head. I'm thinking about buying one and boring it out.

[PGT]

I've got a 4-position and Sig SRD556 on my 553 SBR. Bought spare regulators for my two US rifles.

[Bret]

Bought spare regulators for my two US rifles.

Who did you buy them from?

[JoshNC]

Who did you buy them from?

Gatewood supply is your best bet for SIG spares.

[Bret]

Thanks Josh. I compared the 4-position one that came with my 553RP with the one that came with my 556 SBR. While they will interchange in either rifle, the inside diameter of the 553RP's 4-position valve is smaller than that of the 556 SBR's valve. As a result, the 556 SBR's piston will not fit inside the cup of the 553RP's. I did notice that the 553RP's valve is marked 12, 13, 14, 15. I'm guessing that these numbers represent the diameter. The 4-position that JDI is selling on their website are marked X, 0.9, 1.2, 1.3. I'm assuming those are small diameter holes meant for 5.56x45 rifles. All this has me wondering if the valve cup sizes are different in order to prevent putting a 7.62x39 valve with the larger holes in a 5.56x45 rifle. Assuming you have one, would you mind measuring the inside diameter of the cup of your 4-position 5.56x45 valve? My 556 SBR runs like a champ, but it's obviously overgassed. I'd like to fix that.