I'd love a proper length 300BLK. Sadly, SIG doesn't make one. They offer an 8.9" 5.56 and a 12" 300BLK; optimal lengths are reversed.

I agree on the .300BLK barrel length being silly, on the 553. However, they utilize some sort of reflex silencer on it, which may provide an optimal setup; albeit one unavailable to us. I intend to make a shorty .300BLK on a US 556 receiver, eventually; I have had the chambered barrel blank and host receiver for a while, but have yet to get the ball really rolling with the gunsmith. I know some folks out there have cut down their SAN .300BLK 553 barrels, which is likely what I'd do, if I had one of those guns; I'm just not interested in that caliber enough to invest in that particular gun for it.

Yep. I think there might be a reason for the longer barrel as far as reliability goes. I'd be interested to know if those who've cut down to 8-9" find them to run as they should. Certainly would need a 4-pos regulator to fine-tune operation.

what SIG AG told me regarding the 300blk 553 was that they couldn't get it to run reliably with a barrel shorter than the 12" iirc.

Surely it's more a matter of dwell time, than barrel length. With a barrel that long, they could have gone with the 551 operating system, but didn't; no doubt due to the longer dwell time of the 553LB configuration. It's odd though, considering the efficiency of the 55X, that they'd have to do that. AR15s run into problems, when the muzzle gets too close to the gas port; the 553 and 551 are evidence that the Sigs aren't hindered to the same extent.

quote:

Originally posted by KSGM:
Surely it's more a matter of dwell time, than barrel length. With a barrel that long, they could have gone with the 551 operating system, but didn't; no doubt due to the longer dwell time of the 553LB configuration. It's odd though, considering the efficiency of the 55X, that they'd have to do that. AR15s run into problems, when the muzzle gets too close to the gas port; the 553 and 551 are evidence that the Sigs aren't hindered to the same extent.

yeah, if the 553 blk or 553r were shorter I'd prob opt for those. The krink/mp5 length on the 553SB is really convenient for me though. Diopters always look cooler too. I'll probably go for that when i can.

Vickers Guide just posted this pic. Seems a shorter barrel has been offered in 300BLK?

I believe that to be the reflex silencer I mentioned. The unfluted portion of the silencer body is likely where the muzzle threads are.

Also, I wish he'd hurry up and release that book.

August ship date I think

August has come and gone. I wish that book would come out too!

As to the 300 black out 553 barrel length, I was told the reason Sig made the rifle with a 12" barrel, was they didn't understand why anyone would want to lob 200 grain bullets that hit with for force of a 22 lr when it comes to energy. That made some sense to me and I just assumed the swiss were stuck on high velocity fun rather than making super quiet rounds.

quote:

Originally posted by krieg:
from B&T USA

"We are going to be offering the 5.56/7.62 RBS Suppressors for the SIG55X platforms this year. We will have the NATO flash hider and the locking collar version available.


Best regards,

B&T USA"

well, I'll definitely get one for my 550. is there any point to running subsonic 556 or is it best to just use standard loads.

B&T USA has released the Rotex cans in the USA that work with the the A2 mount. The mount on the Rotex is removeable correct? And the difference between the Rotex cans and the Swiss B&T can that fits the STGW 90 is just a different mount?

STGW 90 B&T




ROTEX-X 5.56MM B&T USA

This message has been edited. Last edited by: gw3971,

I believe you are correct, in saying the current-manufacture Rotex A2 mounts are removable from the silencer body. The STGW90-specific silencer's mount is not removable though, and seemingly not produced or sold separately from the silencer itself. The Rotex pictured in your post could be utilized on some of the current LB variants I have seen.

I sent you an email, regarding a couple 55X silencer-related things.

KGSM, thanks for the e-mail. I don't have a can that uses the hub system and I don't have a 551 either.

I have a 553 LB that I am looking to suppress with a 1 piece barrel. Looks like the GP90 nato, and Gemtech halo, might work with it and I think the B&T Rotex will work with it. Would have been nice to get the B&T to use with the 550 and 551 but sounds like that wont work.

I think I will stop hoping for a 550 can as it is already damn long rifle. I will try and find a dealer here in Utah with a Rotex in stock to make sure.