Over Gassed

[Jackie Graham]

I hear this a lot on this forum. I am still have yet to understand the concept. Let me explain.
First when firing a firearm, the gas from the powder pushes the projectiles down the barrel until it exits. While the projectile is moving through the barrel the gas continues to build until the projectile exits or all the powder is burned.
The amount of gas is determined by the powder and the volume of space that is has to burn. So the longer the barrel, the more gas. Now from what I have seen a read, most barrels have a standard size gas port and depending on the length they have standard gas systems, carbine, mid and rifle.
So why would say a BCA or PSA barrel be over gassed and a higher price barrel not?
The logics just don't make sense if all other components are the same.

 

[JBWJr]

I think it has to do with illegal immigrant employees.
Oh, you meant the firearm? Sorry. Never mind.

 

[Jackie Graham]

I get over gassed when I eat chili, lol. Same concept. The amount of beans x the volume of space allows gas to build until it exits, lol

 

[CQB27]

Standard size gas port you say?

In the world of cheap AR’s the “standard” is not standardized = over gassed or under gassed rifles. Mostly over gassed because at least they work…for a while.

 

[opps]

It is all about gas port diameter. Some are perfect. Some oversized to allow for cheaper ammo (steel case Russian) that has a lower power powder. Lower price point barrel manufacturers may know their customer will run weaker ammo perhaps.

An adjustable gas block such as Aero or similar would allow you to run open for cheaper ammo and close it down some for normal ammo.

Add a can and an adjustable is almost mandatory.

 

[Fatal_Bert]

There isn't really a "standard gas port size" it varies from manufacture to manufacturer. It can vary in the same batch of barrels from the same manufacturer.

You'll never notice a difference in size with the naked eye or a standard tape measure, it's something that has to be gauged. The difference between being obnoxiously over gassed and slightly under gassed is very small.

Most companies that sell lots of parts and parts kits for your average AR builder sell over gassed barrels because it ensures reliability across a large range of different buffer, bolt carriers, tolerance, and ammunition selections.

Hence the term "muh budget AR runs like a scolded dog, it'll eat anything"

Yes, your BCA barrel is massively over gassed and easily shoots weak steel case ammo as well as green tips. The extra recoil, and gasses slapping you in the face, and extra wear and tear on your moving components are of no consequence because you don't know any better.

For other, more refined gentleman, they prefer a barrel properly gassed for their exact combination of barrel length, buffer, ammunition, suppressor etc. They like a super smooth shooting rifle and that starts at the gass port, no way around it. (Your adjustable gas block is gay and the reason no one likes you)

I'm somewhere in the middle. I like colt and fn military type barrels, not completely over gassed like BCA garbage, but over gassed enough to be reliable in less than ideal situation.

 

[CQB27]

I'm somewhere in the middle. I like colt and fn military type barrels, not completely over gassed like BCA garbage, but over gassed enough to be reliable in less than ideal situation.

 

[MidniteFlame]

There isn't really a "standard gas port size" it varies from manufacture to manufacturer. It can vary in the same batch of barrels from the same manufacturer.

You'll never notice a difference in size with the naked eye or a standard tape measure, it's something that has to be gauged. The difference between being obnoxiously over gassed and slightly under gassed is very small.

Most companies that sell lots of parts and parts kits for your average AR builder sell over gassed barrels because it ensures reliability across a large range of different buffer, bolt carriers, tolerance, and ammunition selections.

Hence the term "muh budget AR runs like a scolded dog, it'll eat anything"

Yes, your BCA barrel is massively over gassed and easily shoots weak steel case ammo as well as green tips. The extra recoil, and gasses slapping you in the face, and extra wear and tear on your moving components are of no consequence because you don't know any better.

For other, more refined gentleman, they prefer a barrel properly gassed for their exact combination of barrel length, buffer, ammunition, suppressor etc. They like a super smooth shooting rifle and that starts at the gass port, no way around it. (Your adjustable gas block is gay and the reason no one likes you)

I'm somewhere in the middle. I like colt and fn military type barrels, not completely over gassed like BCA garbage, but over gassed enough to be reliable in less than ideal situation.

Such great info for an under educated shooter like myself. Thank You Sir!

 

[cmshoot]

If the gas port is properly sized for the caliber/barrel length/gas system length, has the proper buffer/buffer spring for those same criteria, the AR is made of solid parts, it is properly assembled, and you're not trying to run both subs and supers out of it, there is no reason for an adjustable gas block/BCG/etc.

A properly built AR should run suppressed and un-suppressed with no changes or mods to the system when switching in between.

 

[Jackie Graham]

I haven't had any problems as far as I am concerned with any of my ARs. They all run fine with any ammo that I use, factory, reman or my reloads. Ammo will change the gas pressure more than anything. I don't believe that there is any adjustment that you can make to compensate for the unlimited variations that you can get by using different types of ammo. Even when you change from 55g to 63gr to 75gr, your pressure is going to be all over the board. No microscopic difference in the gas port on the barrel is going to make that big of difference.
As long as they run with any ammo you have a rifle that you can count on.
Not one that might not work because your preferred ammo wasn't available.

JMO