I learned something new (to me) about the AR

**Arik** · 05-16-21, 17:45

I knew that but I've seen pump action ARs and AKs. Not to mention LARPing.......i mean dry fire. ....with my first AK when I was 19!!!!! Ahh the carefree days!!!

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**matemike** · 05-16-21, 19:03

I saw a post years back by a newb saying that he knows the gas tube is the single most important part on the M4; so how often should he clean it. That got my mind into thinking about the mechanics and I realized back then what the op is saying.

I would just make sure the gas block is removed or something is in the gas tube hole of the gas block so fire does not come back towards the shooters face.

Lastly I came to my own conclusion that the gas tube is certainly NOT the single most important part. You need a barrel before anything else. Think about it, you could jam a round into a bare barrel and set it off with a hammer and a nail. Shoot, just rock and a nail.

**TomMcC** · 05-16-21, 19:11

Originally Posted by C-grunt

Here is the Colt test I was talking about. I cant find the original video. The gas tube ruptures around 4:25 in the video and he shoots several rounds bolt action style after.

https://www.youtube.com/watch?v=Kzfm4pYhIyY

Thanks.

**AndyLate** · 05-16-21, 19:38

My biggest AR surprise came when I started handloading for them. The design is amazingly tolerant of pressure levels and different powders. It seems that any reasonable load with mid burn rate powders will cycle the gun just fine, at least in "going to the range" temps. I remember reading how a simple switch from stick to ball powders (or vice-versa) caused huge reliability problems in VN and my experience certainly does not bear that out (admittedly the AR has changed a bit since then too).

Compare that to loading for a stock Garand - very narrow range of allowable powders and pressure.

Andy

**lysander** · 05-18-21, 21:20

Originally Posted by C-grunt

Here is the Colt test I was talking about. I cant find the original video. The gas tube ruptures around 4:25 in the video and he shoots several rounds bolt action style after.

https://www.youtube.com/watch?v=Kzfm4pYhIyY

That is actually a Rock Island Arsenal Test of the (then) new heavy barrel.

**MountainRaven** · 05-18-21, 22:30

Originally Posted by AndyLate

My biggest AR surprise came when I started handloading for them. The design is amazingly tolerant of pressure levels and different powders. It seems that any reasonable load with mid burn rate powders will cycle the gun just fine, at least in "going to the range" temps. I remember reading how a simple switch from stick to ball powders (or vice-versa) caused huge reliability problems in VN and my experience certainly does not bear that out (admittedly the AR has changed a bit since then too).

Compare that to loading for a stock Garand - very narrow range of allowable powders and pressure.

Andy

The AR is a lot more tolerant of things when fired semi-auto only than when fired full-auto. Add that to a high humidity, high temperature environment that's intrinsically hostile to everything man-made... Increased cyclic rate, plus increased gas port erosion (due to both firing schedule and possibly corrosion), plus full-auto, plus hostile environment... and now your gun may not work as well as it should. Add neglect due to a lack of available cleaning kits and components. Plus the fact that Colt may or may not have been making guns to a consistent level of quality and there may or may not have been a fixed TDP for the XM16E1... Problems on problems on problems.

The Garand, being a gas trap rifle that was adapted to long-stroke piston, has very short dwell-time, with the gas port being located about an inch from the muzzle.

(On the subject of allegedly very tolerant gas systems: The short-stroke gas piston system. The FN FAL has one, but it has eleven adjustment settings on it and the difference between 1 and 11 is the difference between the gun barely functioning or not functioning at all and the gun beating itself to bits. But an AR with a short-stroke piston is supposed to be entirely self-regulating and über-reliable. And some of them are absolutely, but I question whether the increased reliability is really there.)

**okie** · 05-19-21, 00:55

Originally Posted by matemike

I saw a post years back by a newb saying that he knows the gas tube is the single most important part on the M4; so how often should he clean it. That got my mind into thinking about the mechanics and I realized back then what the op is saying.

I would just make sure the gas block is removed or something is in the gas tube hole of the gas block so fire does not come back towards the shooters face.

Lastly I came to my own conclusion that the gas tube is certainly NOT the single most important part. You need a barrel before anything else. Think about it, you could jam a round into a bare barrel and set it off with a hammer and a nail. Shoot, just rock and a nail.

"Bolt action" ARs have been around for a long time, mostly because of semi auto centerfire laws in GB. All they are is ARs without a gas port in the barrel and normally will use a side charging upper of some sort. Otherwise they're all stock AR.

**lysander** · 05-20-21, 10:55

Originally Posted by MountainRaven

The AR is a lot more tolerant of things when fired semi-auto only than when fired full-auto. Add that to a high humidity, high temperature environment that's intrinsically hostile to everything man-made... Increased cyclic rate, plus increased gas port erosion (due to both firing schedule and possibly corrosion), plus full-auto, plus hostile environment... and now your gun may not work as well as it should. Add neglect due to a lack of available cleaning kits and components. Plus the fact that Colt may or may not have been making guns to a consistent level of quality and there may or may not have been a fixed TDP for the XM16E1... Problems on problems on problems.

The Garand, being a gas trap rifle that was adapted to long-stroke piston, has very short dwell-time, with the gas port being located about an inch from the muzzle.

(On the subject of allegedly very tolerant gas systems: The short-stroke gas piston system. The FN FAL has one, but it has eleven adjustment settings on it and the difference between 1 and 11 is the difference between the gun barely functioning or not functioning at all and the gun beating itself to bits. But an AR with a short-stroke piston is supposed to be entirely self-regulating and über-reliable. And some of them are absolutely, but I question whether the increased reliability is really there.)

Technically, "DWELL TIME" is the time from primer ignition to bolt unlock.

The AR community has been misusing the term for some time.

As to the FAL, the reason its gas system goes from the two extremes is it uses a "bleed on" gas system as opposed the "bleed-off" system almost everyone else used with adjustable gas porting.

**okie** · 05-20-21, 20:22

Originally Posted by lysander

Technically, "DWELL TIME" is the time from primer ignition to bolt unlock.

The AR community has been misusing the term for some time.

As to the FAL, the reason its gas system goes from the two extremes is it uses a "bleed on" gas system as opposed the "bleed-off" system almost everyone else used with adjustable gas porting.

Seriously? I always felt intuitively like that terminology was backwards. Do you have a source for that?