The gross negligence centered around my dating habits lo these many years ago.

How do you time the barrel on an AR-5,M-4 or M-16.
The gas post has to be a given size, and it has to go into a groove x amount of distance from the muzzle or breech end. Is a mandrel with an arrow made up so that when it is in the correct amount of inches/mms you tun the whole assembly so the arrow is TDC, and then drill a succession (spotter/non skid/starter/ cobalt or carbide through and through)bits.

Is the ho deburred the natural way with a deburring tool, or by C'Section?

Hotay, now for hard part; is the breech end of the barrel threaded a given number of turns so that when you come to a stop with the important feed ramps centered at bottom dead center, or do we use a dial gauge to tell us when the dirty deed is done and then we can stop, flush and Gerbils out,and screw it on until hell will not have it?

Tanks

The guys at Krieger told me they always put the gas hole through to the groove. I don't think the others do it that way, I know DPMS don't.

I don't think it has been proven one way or another on the location of the gas hole. That is land or groove.

Generally, the extension is screwed on first, then the port is drilled. If you want the port in a groove, you make sure the extension stops in the correct place when installing it. Drill, ream, debur with ez-bur.

Krieger does it differently. They actually drill and ream the bore, contour and thread the barrel for the extension, then go on the rifling machine and rifle the barrel making sure a groove is cut where the port is. Kinda hard for the average gunsmith to do it this way. Probably would not work well with button rifled barrels either.

Why do knowledgable gunsmiths locate the port in the groove you ask? Because doing so takes less time than answering the phone call from the customer and trying to explain to him why it doesn't matter where it is.

John

Have to agree with Butch. It hasn't been proven an advantage to have the port in the groove or on a land. Most just place it where it works out and you can never tell the difference. Since the port needs to be .093 in most cases you'll find that to be as wide or wider than a lot of grooves in 4 or 6 groove barrels. So in a lot of cases you can't do it anyway.

quote:

Why do knowledgable gunsmiths locate the port in the groove you ask? Because doing so takes less time than answering the phone call from the customer and trying to explain to him why it doesn't matter where it is.

That explains it wonderfully.

I did the math last night on an old HP calculator on how to get it all to line up. Not a task for the inexperienced, nor the faint of heart.

quote:

they always put the gas hole through to the groove

Sure they do. I'd sure like to see how they do that! Carbines can have ports up to .120" and that's wider than the grooves.

quote:

Originally posted by Toomany Tools:

quote:

they always put the gas hole through to the groove

Sure they do. I'd sure like to see how they do that! Carbines can have ports up to .120" and that's wider than the grooves.

I agree with you, but one can also separate the pepper from the fly-$hit when necessary.

quote:

Originally posted by Toomany Tools:

quote:

they always put the gas hole through to the groove

Sure they do. I'd sure like to see how they do that! Carbines can have ports up to .120" and that's wider than the grooves.

Might want to check your port specs before you make your next carbine barrel. We generally use about a .065 on carbine gas systems and .076 on mid gas systems. As a general rule, the longer the gas system, the larger the port. A standard rifle gas system will usually have about a .089-.098, depending on who is making it and what type loads are expected. The largest port that will be needed in any of Kriegers standard contours would be in the 28" match contour that I developed and which they also now offer. This barrel has a gas system 2" longer than a std rifle system. These generally take about a .100 port to run reliably.

John

I got to shoot one of Gasgunner's space guns a while back. It was very smooth. The sights just sat there all nice and quiet while the empties landed in a small pile.

I had gasgunner build one that I gave to a young friend. It is a very accurate and dependable rifle. He knows his business.
Butch