Down vent and sand cut BCG and gas stopping charging handle

[850guns]

A lefty friend of mine purchased a down vent BCG to help with gas in the face. Do they work? Is there a down side?

I've also seen bolt carrier groups with sand cut that supposed to help with dirty weapons.

And I'm trying to decide what gas blocking charging handle to buy. Any favorites?

 

[Themumfordman]

Haven’t seen a down-vent BCG, that would be interesting. I wonder what that would do to your fire control group in terms of gunk and wear.

Personally I’m running Radian SD, Geissele Super Duty and Griffin Snatch. I’ve got the Radian on my 5.56 12.5”, since it’s my gassiest gun and it seems to do the best mitigating it. The Griffin works pretty dang well though and is typically a fair amount cheaper.

 

[Little Jack]

*not an engineer

The lower already gets dirty when shooting suppressed with a standard carrier. I'd be hesitant to try one that forced more gas into the mag/fcg area. The write up on KAKS site mentions it being quieter, but that's because they moved the expanding gasses further from your right ear and into a more confined space that's likely to result in filthy mags etc.

Something to consider is the gas in the face isn't necessarily coming from the gas tube. Depending on how the gun is setup you can get a lot back from the chamber/barrel as the bolt unlocks. A commercial 16" carbine gas barrel with a standard spring/buffer is going to be pretty gassy.

I've seen the Gemtech adjustable carriers used and I have a couple of the Bootleg adjustable. The Gemtech was the first readily available option. It only had two settings and required you to remove the bcg to change the setting. Bootleg was shortly behind them with four settings and is adjustable with a flat head from the ejection port side without removing the carrier. The adjustable BCGs are nice because they're quick and easy to install/remove. They're not cheap and you only get one/three more settings besides "normal".

I've tried several gas blocks and my current favorite is the Superlative Arms. A gas block is generally cheaper than a new carrier with more adjustability but isn't quite as convenient as the carriers are. The superlative offers 30+ settings via a screw with ball detent. It's on you to remember how many clicks you did but it's arguably more secure than a single set screw and easier to adjust than the dual screw method with audible/tacticle clicks when you do make a change. They've also got the "bleed off" feature that will vent gas out the front of the block but in my experience that's not necessarily a game changer.

I've got a couple of PRI gas busters that are fine but I'd work on getting the gun gassed properly before popping for a handle.

 

[Themumfordman]

100% agree. Superlative Arms gas block is the best I’ve used, and if you’re shooting suppressed and want to control gas, the buffer, charging handle and gas control all need to be considerations. You grab your basic MK18 and it’ll run anything suppressed or not, but the gas might just kill you. Being able to tune your setup will make all the difference in the world, and keep the gun as clean as you can (bit of a losing battle with a suppressor but you do what you can).

 

[850guns]

My friend said the gasses go down the magazine. I'm not really interested personally. Just saw it on the kak website reminded me of my lefty friend.
Also saw they offer bcgs with sand cuts. I've seen sand cut bcgs from other manufacturers. It must work, cause I see them more? What yall say?
Definitely gonna wait on the charging handle purchase till I learn more.

 

[Themumfordman]

I will fully admit to not ever having tried to bury my gun in sand and see if it still ran. Not something I feel at all qlalified to comment on…

On the down-blow bolt thing, I do know that there are a couple of bullpup designs (like the old P90) that discharge brass straight down, so I’d have to imagine that with that type of operation it would be easy to divert gasses the same way. Blowing them into a magazine though sounds like a terrible idea by comparison.

 

[Little Jack]

My friend said the gasses go down the magazine. I'm not really interested personally. Just saw it on the kak website reminded me of my lefty friend.
Also saw they offer bcgs with sand cuts. I've seen sand cut bcgs from other manufacturers. It must work, cause I see them more? What yall say?
Definitely gonna wait on the charging handle purchase till I learn more.

If you've seen a mag after normal suppressed shooting you know it and any remaining ammo are filthy. Sending more gas directly to that area is creating a problem worse than what it's "fixing".

 

[850guns]

If you've seen a mag after normal suppressed shooting you know it and any remaining ammo are filthy. Sending more gas directly to that area is creating a problem worse than what it's "fixing".

I agree. But if I had a gassy gun and I was a lefty, it might have more need.

 

[Themumfordman]

Someone makes lefty uppers, I just can’t remember who off the top of my head. BCG and receiver are different, but I think everything else can stay the same as a standard upper. That would be a much better fix for a lefty, and again gas block & buffer to tune it.

 

[Little Jack]

Stag. Recently bought by Aero

ETA "by"

 

[Little Jack]

Stag. Recently bought Aero

ETA. RDB is a pleasure to shoot suppressed.
The best factory adjustsble gas system I've used and the downward ejection makes for a long operating stroke with no direct route/seams for gas to get to you.

 

[850guns]

Someone makes lefty uppers, I just can’t remember who off the top of my head. BCG and receiver are different, but I think everything else can stay the same as a standard upper. That would be a much better fix for a lefty, and again gas block & buffer to tune it.

Yes but options are limited, especially short barrel and caliber options.

 

[850guns]

ETA. RDB is a pleasure to shoot suppressed.
The best factory adjustsble gas system I've used and the downward ejection makes for a long operating stroke with no direct route/seams for gas to get to you.

Lol, just told him recently that the rdb was on sale.

 

[Little Jack]

Yes but options are limited, especially short barrel and caliber options.

Aero sells just the upper. Pair it with one of their LH 556, 6.5G or 6.8 BCGs and you've got at least 6 chamberings available.

Search results for: “Left hand” | Aero Precision

www.aeroprecisionusa.com

 

[Themumfordman]

I think if you have a specific setup you want in a lefty style you’re pretty much stuck building, at least the upper portion. It’s the way I’d go anyway if I was wrong handed.

 

[Themumfordman]

Stag. Recently bought by Aero

ETA "by"

Is that for real? Aero got bought out by stag?

 

[Little Jack]

Is that for real? Aero got bought out by stag?

Aero bought Stag

 

[850guns]

*not an engineer

The lower already gets dirty when shooting suppressed with a standard carrier. I'd be hesitant to try one that forced more gas into the mag/fcg area. The write up on KAKS site mentions it being quieter, but that's because they moved the expanding gasses further from your right ear and into a more confined space that's likely to result in filthy mags etc.

Something to consider is the gas in the face isn't necessarily coming from the gas tube. Depending on how the gun is setup you can get a lot back from the chamber/barrel as the bolt unlocks. A commercial 16" carbine gas barrel with a standard spring/buffer is going to be pretty gassy.

I've seen the Gemtech adjustable carriers used and I have a couple of the Bootleg adjustable. The Gemtech was the first readily available option. It only had two settings and required you to remove the bcg to change the setting. Bootleg was shortly behind them with four settings and is adjustable with a flat head from the ejection port side without removing the carrier. The adjustable BCGs are nice because they're quick and easy to install/remove. They're not cheap and you only get one/three more settings besides "normal".

I've tried several gas blocks and my current favorite is the Superlative Arms. A gas block is generally cheaper than a new carrier with more adjustability but isn't quite as convenient as the carriers are. The superlative offers 30+ settings via a screw with ball detent. It's on you to remember how many clicks you did but it's arguably more secure than a single set screw and easier to adjust than the dual screw method with audible/tacticle clicks when you do make a change. They've also got the "bleed off" feature that will vent gas out the front of the block but in my experience that's not necessarily a game changer.

I've got a couple of PRI gas busters that are fine but I'd work on getting the gun gassed properly before popping for a handle.

Never used an adjustable bcg, good to know that they work.
+1 for adjustable gas blocks, trying to learn the Dictator, aero precision and strike industries agb.

Who is PRI?

 

[Little Jack]

Never used an adjustable bcg, good to know that they work.
+1 for adjustable gas blocks, trying to learn the aero precision and strike industries agb.

Who is PRI?

Precision Reflex

Manufacturing and supplying everything for the experienced firearm enthusiast—and arming the country’s bravest members of the military and law enforcement.

www.precisionreflex.com

 

[joebagodonuts]

As someone who shoots lefty, the first time I shot my 12.5" with a high back pressure can was miserable. Swapped the H2 for an H3 buffer, added the KAK downward venting carrier and a Raptor SD charging handle. With these changes the gas to face is minimal and basically a non-issue. Have run about 800 rounds thru it in this configuration, all suppressed, with no issues to speak of.

Some good side by test videos exist with the downward venting carrier, but I think the amount of extra fouling is exaggerated by people who mistake gas for debris. You are getting both out the side vents in a standard carrier, but if you watch some slo-mo footage you will see most of the "gas" is just that, gas. Will it eventually foul up a mag and create reliability issue? Maybe, but there are some really dirty magazines floating around rental ranges/armories that run full auto suppressed for thousands of rounds and they work fine for many more rounds than the average Joe is going to put thru his build.