[Gus Fisher]

Got a kick out reading this that Art posted below: "The three B's are an excellent suggestion, I prefer, "The 4 B's", to include the Band. Keep us posted. Art"

Of course Art is absolutely correct that everything having to do with the front band and the gas cylinder is very, VERY important to accuracy with the M14. Unlike a bolt action rifle, there are a bunch of things "hung" on an M14 barrel and some of them do things while the rifle is operating.

Without rewriting half the posts on the "Barrel Harmonics" thread, let me just say that it is much better for harmonics and accuracy when all the "stuff" that is hung on the barrel allows the barrel harmonics to be as smooth and uniform as possible. You also want the best in uniformity or what some others call "repeatability" in the way the parts function and even come to rest, for the best accuracy. You can do these things by:

1. Shimming and unitizing the gas cylinder
2. Selecting the piston that gives the best accuracy
3. Correctly shortening the gas plug for good "dwell time" or "timing of the op rod" as we called it.
4. Gluing the op rod guide on the barrel
5. Gluing the rear handguard up front and in back to the clip
6. Ensuring the whole band and cylinder is centered in the stock
7. Ensuring there is proper tension between the front band and stock ferrule
8. Ensuring the front band does not touch and especially doesn't rub on the front of the stock ferrule.
9. Ensuring the cylinder part of the gas cylinder doesn't rub hard in the stock
10. Ensuring the bottom of the op rod guide doesn't rub in the stock during firing

 

[art luppino]

Plllus One for Gus..

Got a kick out reading this that Art posted below: "The three B's are an excellent suggestion, I prefer, "The 4 B's", to include the Band. Keep us posted. Art"

Of course Art is absolutely correct that everything having to do with the front band and the gas cylinder is very, VERY important to accuracy with the M14. Unlike a bolt action rifle, there are a bunch of things "hung" on an M14 barrel and some of them do things while the rifle is operating.

Without rewriting half the posts on the "Barrel Harmonics" thread, let me just say that it is much better for harmonics and accuracy when all the "stuff" that is hung on the barrel allows the barrel harmonics to be as smooth and uniform as possible. You also want the best in uniformity or what some others call "repeatability" in the way the parts function and even come to rest, for the best accuracy. You can do these things by:

1. Shimming and unitizing the gas cylinder
2. Selecting the piston that gives the best accuracy
3. Correctly shortening the gas plug for good "dwell time" or "timing of the op rod" as we called it.
4. Gluing the op rod guide on the barrel
5. Gluing the rear handguard up front and in back to the clip
6. Ensuring the whole band and cylinder is centered in the stock
7. Ensuring there is proper tension between the front band and stock ferrule
8. Ensuring the front band does not touch and especially doesn't rub on the front of the stock ferrule.
9. Ensuring the cylinder part of the gas cylinder doesn't rub hard in the stock
10. Ensuring the bottom of the op rod guide doesn't rub in the stock during firing

Gus, The above is a super list, I hope everybody makes a copy of it. This should have been done along time ago. Certainly there is at least one item each of us would like to see expanded. This is one of my choices, if I only have one. I remember Bill Donovan telling me, " The tighter the better". well, I have an issue with that now.

In your experiences, the question of front draw pressure had to be an issue. I know you can not give us a standard, but as a general statement, what or how much draw pressure would YOU suggest be built into the front end? Would you have different amounts for different use of the rifle. For example, a rifle used for across the course vs one used for slow fire only. Art

 

[Gus Fisher]

"I remember Bill Donovan telling me, " The tighter the better". well, I have an issue with that now.

In your experiences, the question of front draw pressure had to be an issue. I know you can not give us a standard, but as a general statement, what or how much draw pressure would YOU suggest be built into the front end? Would you have different amounts for different use of the rifle. For example, a rifle used for across the course vs one used for slow fire only. Art"

I first heard Bill Donovan expound the virtues of EXTREMELY tight "draw" or pressure on the front band to stock fit in 1975. As an almost brand new RTE Armorer, I wasn't sure even then if that was such a good thing, but since I was so new - I shut my mouth and listened. A lot of what Bill said proved more than correct and I think this was how Bill was trying to compensate for the very light contour of the then current NM barrel in standard G.I. barrel outside dimensions. However, I think it was more SWAG than fact when Bill said it.

A few months later when I first came up on THE Marine Corps Rifle Team as the junior armorer, I asked the senior armorers -the then Gunnery Sergeants Ted Hollabaugh and Dempsy Damron about that. We did some experimenting on it and found an extremely tight fit caused the front band to dig into the stock ferrule too much. That caused "squeeking" and other sounds that showed the front band could not be seating back to the same position after every shot. So we backed off to less, but repeatable tension.

In the years to come we had a chance to try different amount of pressure and concluded that much pressure or tension was indeed too much. Now, one has to know we had also gone to full heavy barrels in that time and even had begun to use the medium heavy barrels. What I personally believe is the medium and full heavy barrels with their larger contours were stiff enough to offset the "whippiness" of the older light NM barrels.

During this time, we also threw away our old "glassing doughnuts" as we called them because they gave too much tension and all too many times they caused the front band and stock ferrule to be "off" when the glass set up. They caused a great deal of sanding to get the front band to center on the ferrule and move smoothly and freely. When someone hit on the idea of using coat hanger wires, that was a very simple way to get enough, but not too much tension on the front band.

As we switched over to the McMillan fiberglass stocks, we went to the smaller coat hanger wire that we got from the cheap wire coat hangers most dry cleaners use. With the fiberglass stocks, it wasn't as necessary to put quite as much tension as on wood stocks because fiberglass stocks don't swell and shrink due to humidity.

When I glass bed a rifle today, I only use the thicker coat hanger wire on really worn wood stocks and sometimes use the thinner wire, depending on what kind of draw there is on the stock to begin with. If there is little to no draw, I use the thicker wire. If there is some draw, I use the thinner wire. What I'm after is just enough tension to keep the front band to come back to the same position after every shot.

 

[Nemosengineer]

Thank you Gus Fisher, and Art Luppino, for providing such insight as to the modifications that goes into building a match rifle. Draw pressure has been a question in the back of my mind for a long time, thanks to both of you for this fine discussion.

: Mike NAV1