Save weight and regulate recoil with your BCG ... Say What ?

[Varminterror]

I don’t believe this adjustable gas key/carrier will produce as clean of action as an AGB. The gas is still reaching the key, and pushing on that adjustment screw, effectively acting like a DI, as the only space the gas throttled by the screw could then expand is between the key and tube. I could argue it would actually vent MORE junk into a less favorable portion of the action than a standard set up, since forcing more around the tube from the key is NOT where I want venting. An AGB, on the other hand, doesn’t allow as much gas (and everything it’s carrying) to reach the action.

That’s not favoritism, that’s simple fluid dynamics...

 

[Coal Dragger]

What port diameter should I use for my next rifle barrel? The one it is replacing runs about half of the time with a 50 Vmax and half of the time with a 77 smk, and half of the time with a brake, the other half with a SiCo Omega. Oh, and I just got an OSS out of jail...

If you can find the info Crane Surface Warfare Center has some data on gas port sizes specified by .mil for running 5.56.

 

[IndianaBoy]

If you can find the info Crane Surface Warfare Center has some data on gas port sizes specified by .mil for running 5.56.

His point was that for people shooting a wide variety of ammo, or those using suppressors, optimal gas port diameter is not a static number. My rifles that are equipped with suppressors benefit greatly from adjustable blocks.

 

[<*(((><]

Yup correct port sizes matter when all you shoot is m193, ss109 and m855 from a standardized piece of equipment. But for those shooting a wide range of ammo from varying gas system lengths, barrel lengths, suppressed and unsuppressed, etc I’ll take an adjustable gas block over a “correct gas port size.”

 

[RecoilRob]

The only way I can see this adjustable carrier would be advantageous is if it would vent the gas BEFORE it got to the piston chamber. If all of the gas went out the side without applying any force to the piston....effectively there is no 'DI' happening and the pressure in the tube and key would be minimized. The downside is you'd get a bunch of gas blowing out of the port where an AGB restricts it to a minimum...which seems a better way to go about things. With a can and if it's actually venting the gas without allowing it to get to the piston....that'd be one smoky bugger to shoot even if it didn't recoil badly. And if it only restricts the gas flow to the piston....I fail to see the advantage over an AGB other than convenience to adjust through the ejection port.

 

[someguy2800]

I could be wrong but I don't believe this is venting anything. I think its just a bolt carrier with a screw to restrict gas flow in the side of it. That's handy because it would allow you to adjust your gas through the port door on a rifle where you can't reach the adjustable gas block with the handguard in place. But Varminterror is right, whatever is restricted from entering the bolt carrier will blow out the gas tube and key. It has to go somewhere.

 

[IndianaBoy]

I feel like I should point out that low mass carriers are NOT designed to save overall weight. They are designed to reduce reciprocating mass.


If you want to shave weight in your rifle, do it in the barrel, stock, and maybe optic. A low mass carrier should come after a comp and with an adj gas block.

 

[Varminterror]

I’m not one who believes in venting gas for any reason. If I wanted reduced performance, I’d run a smaller cartridge - so when I spend my money and charge the powder, I want the results the powder charge warrants, not some reduction to accommodate an oversized gas system. Throw a throttling valve - an AGB - in the mix and bingo, mitigated and managed action operating pressure, AND maximized cartridge performance.