Suppressor optimized gas port?

[JGifford]

Why not just run the correct gas-port size? This is a friend shooting his rifle with one of my suppressors in place. It functions just fine unsuppressed, too. No adjustable anything and no swapping of anything. It's just correctly gassed/buffered is all.

[JGifford]

According to my fans, I haven't had any problems with length without the SBC. Maybe it's just you.

SBC?

[Former11B]

SBC?

Suppressed Bolt Carrier

That's kind of my idea. Build a gun that's supposed to be suppressed most of the time. The only time the can comes off is when the gun needs cleaned or just to break the carbon loose.

With regard to the SBC; does the "selector switch" get fouled or jammed with extended use? That's one of the complaints I've seen with most everything that restricts gas flow.

That's what I like about my WAR upper; no matter what you shoot through it, the selector switch never gets jammed up. Although replacing an upper isn't always possible, especially for those running a monolithic upper, or matching upper/lower sets, etc. But if you're building a rifle from the ground up you know you'll run a can on, it's worth a look

[mtdawg169]

Why not just run the correct gas-port size? This is a friend shooting his rifle with one of my suppressors in place. It functions just fine unsuppressed, too. No adjustable anything and no swapping of anything. It's just correctly gassed/buffered is all.

Most quality barrels are correctly ported for unsuppressed use only. As I'm sure you're aware, suppressors increase pressure, gas blowback, etc. The Sionics reduced gas port barrel has a slightly smaller port and was designed to be run suppressed the majority of the time. So it addresses those issues at the source, as opposed to the gas block or carrier. Essentially performing the task of an AGB, without the moving parts. The port is still large enough to function unsuppressed with most ammunition. You could take additional measures to reduce gas even further with an AGB. I'm not sure that barrel would do well with a gemtech carrier though. Other companies have made RGP barrels in the past, but not as a regular production item.

[gatordev]

Why not just run the correct gas-port size?

This x10. I see so many people adding all kinds of gear to multiple rifles just to make it run correctly when starting with a spec barrel and buffer would eliminate all of the fiddling. I CAN see the SBC being a nice addition to help with some gas face, but I wouldn't call that a necessity.

Most quality barrels are correctly ported for unsuppressed use only. As I'm sure you're aware, suppressors increase pressure, gas blowback, etc.

I have one (1) AR (.308) that doesn't run right and it's because I mistakenly thought it was going to be different than "all of the other" barrels. Sadly it's not. So hopefully the SBC will be the answer. Otherwise, all of my "quality barrels" (KAC, Colt, Noveske, Douglas) run absolutely fine both unsuppressed and suppressed without ripping out casings or causing malfunctions.

To me, it seems like the Scionics barrel has a bunch of marketing behind it, and its "undergassed port" that lets it run in both modes just means it's gassed correctly. That doesn't make it a bad product. On the contrary, actually, as that seems like just what you want.

[mtdawg169]

This x10. I see so many people adding all kinds of gear to multiple rifles just to make it run correctly when starting with a spec barrel and buffer would eliminate all of the fiddling. I CAN see the SBC being a nice addition to help with some gas face, but I wouldn't call that a necessity.



I have one (1) AR (.308) that doesn't run right and it's because I mistakenly thought it was going to be different than "all of the other" barrels. Sadly it's not. So hopefully the SBC will be the answer. Otherwise, all of my "quality barrels" (KAC, Colt, Noveske, Douglas) run absolutely fine both unsuppressed and suppressed without ripping out casings or causing malfunctions.

To me, it seems like the Scionics barrel has a bunch of marketing behind it, and its "undergassed port" that lets it run in both modes just means it's gassed correctly. That doesn't make it a bad product. On the contrary, actually, as that seems like just what you want.

I'll be honest, Sionics hasn't marketed that barrel AT ALL, with the exception of the intro thread on M4C. It's all been word of mouth. And I've been very satisfied with mine. It's is 0.006 under the "correct" size for an 11.5" barrel. And I wouldn't recommend it for someone who wasn't shooting suppressed the majority of the time. It might be more accurate to say that it is "correct" for a dedicated suppressed upper. And right now, no one else offers a comparable product. Side by side with a BCM 11.5, the Sionics has less blowback and is a shade softer shooting, with all other components being the same. With the suppressor removed, it's also more ammo sensitive. So, there's the trade off.

It's a great option, but obviously not the only solution. For someone like me that doesn't really trust adjustable gas blocks and doesn't want to fool with switches on the carrier or receiver, it's a better mousetrap. Mainly because it's "correct" for suppressed shooting.

[usbp379]

We're using .070" as correct 11.5" gas port?

[gatordev]

I'll be honest, Sionics hasn't marketed that barrel AT ALL, with the exception of the intro thread on M4C. It's all been word of mouth. And I've been very satisfied with mine. It's is 0.006 under the "correct" size for an 11.5" barrel. And I wouldn't recommend it for someone who wasn't shooting suppressed the majority of the time. It might be more accurate to say that it is "correct" for a dedicated suppressed upper. And right now, no one else offers a comparable product. Side by side with a BCM 11.5, the Sionics has less blowback and is a shade softer shooting, with all other components being the same. With the suppressor removed, it's also more ammo sensitive. So, there's the trade off.

Gotcha. That makes a little more sense. And no surprise that's there's a trade off. Nothing's free, right?

[Default.mp3]

Another option for an adjustable carrier, if you can't find the Gemtech or are leery of the components used (I've heard complaints about the staking and the screws used for the gas key being subpar): http://bootleginc.com/product/bootle...table-carrier/

You could also get something like the MicroMOA Baby Govnah or Black River CustomTune Port, which are gas-restricted gas blocks, so you can tame down an overgassed barrel, but still keep the simplicity of a non-adjustable gas block.

[mtdawg169]

We're using .070" as correct 11.5" gas port?

Correct is a relative term in this case. There is no true "correct" in this case because there is no spec for it. "Optimal" may be a more accurate description. That is the port size they chose after months of testing. The RGP barrel was the result of a LE Department request for dedicated suppressed uppers. Sionics could have gone a tad smaller, but the gun would have been truly a dedicated suppressed upper ONLY. So they built in a margin of error by opening it back up to 0.070. They do not guarantee function without a suppressor. However, in my own experience the gun runs well without a suppressor, even with weak .223 ammo, an A5H3, springco Green and LMT enhanced carrier. So it seems they did indeed find the sweet spot for suppressed 11.5" port sizing.

[mtdawg169]

Another option for an adjustable carrier, if you can't find the Gemtech or are leery of the components used (I've heard complaints about the staking and the screws used for the gas key being subpar): http://bootleginc.com/product/bootle...table-carrier/

You could also get something like the MicroMOA Baby Govnah or Black River CustomTune Port, which are gas-restricted gas blocks, so you can tame down an overgassed barrel, but still keep the simplicity of a non-adjustable gas block.

I really like the BRT custom tune port concept. It allows you to reduce the port size and use any barrel you want.

[usbp379]

I believe (but could be wrong) that Colt uses .070" on their 10.3 and 11.5" barrels.

[mtdawg169]

I believe (but could be wrong) that Colt uses .070" on their 10.3 and 11.5" barrels.

0.070-0.071 is ideal for 10.5, so it wouldn't surprise me if they are using it. But I have no idea what they use on the 11.5. I'd love to see some confirmation of that though. The better manufacturers are usually around 0.076, so it would be interesting to know if Colt is doing something different.

[Slippers]

Another option for an adjustable carrier, if you can't find the Gemtech or are leery of the components used (I've heard complaints about the staking and the screws used for the gas key being subpar): http://bootleginc.com/product/bootle...table-carrier/

You could also get something like the MicroMOA Baby Govnah or Black River CustomTune Port, which are gas-restricted gas blocks, so you can tame down an overgassed barrel, but still keep the simplicity of a non-adjustable gas block.

Bootleg is making the gemtech SBC as far as I can tell. The carrier has identical sand cuts and styling. The only difference is the bootleg allows adjustment without removing the carrier and has 5 settings, although preliminary reports suggest that it isn't as well tuned as the two settings of the SBC.

[Default.mp3]

Bootleg is making the gemtech SBC as far as I can tell. The carrier has identical sand cuts and styling. The only difference is the bootleg allows adjustment without removing the carrier and has 5 settings, although preliminary reports suggest that it isn't as well tuned as the two settings of the SBC.

You're probably right; looking at the pictures, it appears that the Bootleg also uses YFS screws for the gas keys, which was the complaint on the Gemtech carrier that I saw. I've also heard similar things about the Bootleg being somewhat overgassed even on the lowest setting (an issue I've certainly had with my PWS MK110's adjustable gas block).