Rifling?

[captain-ahab]

Ok, this definitely fits into the "for the most part" of this section.

I consider myself a pretty mechanically minded person, but lately I've been trying to figure out how on earth a machine can rifle a barrel of a gun and I'm completely stumped. What could do that to a tube of metal?

Hope some of you hunters may help out a puzzled guy.

Thanks

(EDIT)
Ok, did a little research, found this great article: http://www.firearmsid.com/Feature%20Articles/RifledBarrelManuf/BarrelManufacture.htm

[Bob T]

A long rod with a ball on the end is drawn thru the barrel with a twisting pull...the ball has cutters which cut the grooves

[Z Fisher]

I saw a show about how the Colt M4 is made and they showed the barrel drilling, the reaming and then the groove cutting. It was the reaming that I found most interesting. The don't drill the barrel to the final diameter, they essentially stretch it to the final diameter. And as you've discovered, the rifling is just another machine that essentially sticks a chisel down the barrel and etches the grooves. Very cool stuff.

[flygirl]

What they use are gun drills....consists of a Carbide tip brazed ( welded) onto a hardened steel shank of different lengths...the shank has been precisely straightened by hand using a vise. It used to be a long tedious process which requires the use of Carbide grinders for the tips & milling machines for the shanks...its all then sandblasted before they're shipped out. The sizes range from tiny to massive...they use the massive ones for the big guns. At least this was how it was done when I worked at Eldorado Tool back in the 80s...there for 8 yrs & I can still smell the oil.