Gas Busting Charging Handles

**metroplex** · 04-14-24, 10:01

I used to run the PRI Gasbuster charging handle and felt it was fine even with the Polonium can. A friend shot the 10.5" SBR and after 5 shots handed it back because the gas was burning her eyes. Fast forward to me testing out high backpressure cans with the SiCo GDCH V2 (v2 uses screws and not roll pins for the latch) and noticed that it really blocked the gas from coming back. However, after awhile there was enough carbon/gunk that built up at the top of the charging handle and eventually just sprayed all over my face.

My M Frames were starting to get hazy and I couldn't figure out why until I took them off and saw they were coated in oil/carbon and my face was sprayed with black gook as well. It looked like the GDCH O-ring at the bottom helped push all the stuff towards the top of the handle and once it built up enough residue it dislodged into my face.

The PRI Gasbuster has channels on the bottom the focus the spray to the right/ejection side of the gun. I'd see that side of my upper receiver coated in the carbon sludge so I Knew the gasbuster was doing its job. But the gas does tend to come up a bit and sting my eyes but I'm not sensitive to that stuff.

Once I tested all the cans and got to the Ventum 762, the flow-through can sold me as it was like running a fully tuned AR15 but not having to tune for anything. Was quiet and I could feel the bolt slow down even more than running unsuppressed. The people that say they'll never mess with conventional baffle suppressors after using a flow-through/HUX/OSS are 110% right. I like the Polonium and AAC Ranger 5, but couldn't hear a difference with the supposedly louder Ventum 762 but the Ventum 762 definitely had far far less backpressure. Like I said before, it was like running a fully tuned AR15 or SCAR (with KNS Discarder on Setting #5 with a Polonium) but without tuning anything.

**Ron3** · 04-14-24, 14:51

Originally Posted by metroplex

I used to run the PRI Gasbuster charging handle and felt it was fine even with the Polonium can. A friend shot the 10.5" SBR and after 5 shots handed it back because the gas was burning her eyes. Fast forward to me testing out high backpressure cans with the SiCo GDCH V2 (v2 uses screws and not roll pins for the latch) and noticed that it really blocked the gas from coming back. However, after awhile there was enough carbon/gunk that built up at the top of the charging handle and eventually just sprayed all over my face.

My M Frames were starting to get hazy and I couldn't figure out why until I took them off and saw they were coated in oil/carbon and my face was sprayed with black gook as well. It looked like the GDCH O-ring at the bottom helped push all the stuff towards the top of the handle and once it built up enough residue it dislodged into my face.

The PRI Gasbuster has channels on the bottom the focus the spray to the right/ejection side of the gun. I'd see that side of my upper receiver coated in the carbon sludge so I Knew the gasbuster was doing its job. But the gas does tend to come up a bit and sting my eyes but I'm not sensitive to that stuff.

Once I tested all the cans and got to the Ventum 762, the flow-through can sold me as it was like running a fully tuned AR15 but not having to tune for anything. Was quiet and I could feel the bolt slow down even more than running unsuppressed. The people that say they'll never mess with conventional baffle suppressors after using a flow-through/HUX/OSS are 110% right. I like the Polonium and AAC Ranger 5, but couldn't hear a difference with the supposedly louder Ventum 762 but the Ventum 762 definitely had far far less backpressure. Like I said before, it was like running a fully tuned AR15 or SCAR (with KNS Discarder on Setting #5 with a Polonium) but without tuning anything.

Agree. Of my first two rifle cans one was a Flow 556k on a Mini-14 Tactical. No gas face.

My next rifle can is probably going to be a Ventum 7.
62.

**markm** · 04-15-24, 09:08

Originally Posted by Ron3

Agree. Of my first two rifle cans one was a Flow 556k on a Mini-14 Tactical. No gas face.

I'm interested in this flow can stuff. When the marketing first came out, I thought it was all B.S. At this point, I avoid shooting suppressed gas guns as much as possible. Sometimes hard when your buddies want you to try their set ups though.

**tangolima** · 04-15-24, 11:09

My state doesn't allow suppressor, so I can only imagine the issue being discussed here. Have you guys tried side charging upper? It doesn't have the rear charging handle and the channel is plugged by a gasketed screw.

There are 2 vent holes in the bcg. I would consider enlarging and tapping them. The larger holes help vent out excessive gas more efficiently after unlocking. The tapped threads give me flexibility to sleeve or plug them when needed.

And of course how about the adjustable gas block?

-TL

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**markm** · 04-15-24, 11:21

Originally Posted by tangolima

And of course how about the adjustable gas block?

Blocks and BRT tubes help tame the bolt speed. But the gas is still trapped in the gun, and there's still REAL exposure to vaporized heavy metals. Even on the Hux can video I watched, the shooter donned a Gas mask for a full auto dump.

**tangolima** · 04-15-24, 12:18

I don't get to tinker with a can, so I could well be totally wrong. Do bear with me

.

Gas find the path of least resistance to travel. After the bullet exits the muzzle, the path of least resistance is the muzzle, probably not through the gas tube back to the action.

Gas in the action is tapped by the gas port hole before the bullet exits the muzzle (the can opening in this case), or during the dwell time. The can significantly lengthens the dwell time, similar to an extra long barrel with a carbine length gas system. The long dwell time allows excessive volume of gas back to the gas cylinder in the bcg, overwhelming the vent holes, and some of it leaks through the gaps in the charging handle channel and ends up on the shooter's face.

We can close up those gaps (the product that has been in discussion), or we can work on the other factors. Gas block orifice cuts down the gas flow. It should help. Enlarging the vent holes in the bcg provides alternative path of lesser resistance for the gas to escape. It should help too.

-TL

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**1168** · 04-16-24, 07:30

Originally Posted by metroplex

. Was quiet and I could feel the bolt slow down even more than running unsuppressed. .

I’m glad that you had a positive experience, but I promise that bolt velocity is not reduced vs unsuppressed with the Ventum.

Originally Posted by tangolima

Gas find the path of least resistance to travel. After the bullet exits the muzzle, the path of least resistance is the muzzle,

most silencers are designed such that they have a greater resistance to forward gas flow than rearward, so that influences “path of least resistance”. You are right that the extra gas isn’t mostly coming through the tube itself, rather down the bore.

Don’t think of the silencer simply as extra barrel, rather as a balloon with two nozzles, or a capacitor. There’s a volume present with a great deal of pressure, so path of least resistance is a relative term…it’ll still escape in every direction it can until pressure hits zero. Even without a silencer, there is some backflow down the bore, just not as noticeable. Anyone that’s ever had to clean a 240 will have experienced this.

**tangolima** · 04-16-24, 10:18

Originally Posted by 1168

I’m glad that you had a positive experience, but I promise that bolt velocity is not reduced vs unsuppressed with the Ventum.

most silencers are designed such that they have a greater resistance to forward gas flow than rearward, so that influences “path of least resistance”. You are right that the extra gas isn’t mostly coming through the tube itself, rather down the bore.

Don’t think of the silencer simply as extra barrel, rather as a balloon with two nozzles, or a capacitor. There’s a volume present with a great deal of pressure, so path of least resistance is a relative term…it’ll still escape in every direction it can until pressure hits zero. Even without a silencer, there is some backflow down the bore, just not as noticeable. Anyone that’s ever had to clean a 240 will have experienced this.

I think I get the picture now. Thanks. It is a prolonged period of residual pressure. The pressure is too low to maintain the gas seal of the brass, but yet high enough to be felt by the shooter. The period lasts even beyond action unlocking. The spent brass from AR with a can, are they sooty?

I shoot milsurp rifles. Sometimes light loads don't have high chamber pressure developed fast enough for the brass to seal chamber in time. Blow back happens with sooty brass. I guess the situation is somewhat similar.

Back to the charging handle, sounds like there needs to be features to deflect the gas leaking through the channel. Thick wings on an ambi charging handle cover the left and right. There is a ridge machined on the top side. The bottom is iffy. Can a ridge be built there with, say, JB weld? How about doing without the changing handle with side charger? It also eliminates the often hated forward assist.

-TL

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