Colt Python Tapered Bore — How Do They Do That?

[Pat Cannon]

Well, Belgiboy got me reading about the Colt Python, and I read that one secret of its famous accuracy is that the bore actually tapers, so it's about .001" smaller at the muzzle than at the breech. One thing I have failed as yet to find is: how the heck do they do that? I can sort of imagine a cutting tool with blades that retract in toward a center somehow... that'd sure be interesting to see. Anybody know?

[Belgiboy]

The secret of the tapered bore was lost forever with the last of the dwarf artisans that was kept prisoner in the caves of Connecticut. I thought everybody knew that.

I had actually never heard of the tapered bore. The Python has a sleeve around the barrel. Sleeving a barrel is how a lot of benchresters improve a barrel that just wont shoot the way it's supposed to. That is my best guess.

[mitchx3]

If it actually tapered and not just floating BS:

A tapered reamer? (The barrel comes off)

squishing the barrel with rollers

[Pat Cannon]

A tapered reamer? (The barrel comes off)

Hmm, that would work. Now I have to look up how they cut the grooves in barrels.

[Shipyard]

Another option would be a full tapered bore to cut a full lenghti taper. A huge custom pain but i've seen it done.

[1911fan]

I always heard it was gain twist and a long forcing cone, but what do I know.

[Pat Cannon]

I always heard it was gain twist and a long forcing cone, but what do I know.

It had occurred to me that maybe the taper might be basically a really long forcing cone. What's a gain twist? Guessing: a twist that increases its rate as it goes down the barrel? (I've read that the twist rate of the Python barrel is 14:1.)

[Pat Cannon]

I always heard it was gain twist and a long forcing cone, but what do I know.

It had occurred to me that maybe the taper might be basically a really long forcing cone. What's a gain twist? Guessing: a twist that increases its rate as it goes down the barrel?

[Oops, sorry, double post. Oddly, the Wikipedia article on rifling had mysterious blank spaces that crashed FireFox every time I selected them, or looked at them.]

[45usp45]

Before CNC's the work head(where the barrel would be held) would be on a pivot which can be adjusted to get the taper you need.
CNC's can do it with programming.No idea how they did it..didn't gather any data on that.
For rifling I'd make through normal procedures.

[Pinnacle]

I always heard it was gain twist and a long forcing cone, but what do I know.

You know that there is this man in the Notthern Burbs that I could ask and I am sure that he could write a dissertation on this matter. I will inquire and report back.

[JFettig]

Often times when a barrel is made, this happens naturally. When you buy a barrel blank, one end is marked to be the breach end because its tapered, smaller at the exit. Its hard to say what causes it when you don't know the exact mechanics of rifling.

Another way it could be done is by lapping, high end barrels are often hand lapped and if the one end is lapped more than the other, you get a taper.


Jon

[Bessy]

I had heard ruger tapered the barrel on their mini 30's, basically forcing a Russian 7.62 (usually around .311 or 3.12) down a nato 7.62 barrel. The result however wasn't increased accuracy. Infact mini 30's are notoriously less accurate than their mini 14 brothers.... I don't see why squishing bullet would make it more accurate...

[EJSG19]

I had heard ruger tapered the barrel on their mini 30's, basically forcing a Russian 7.62 (usually around .311 or 3.12) down a nato 7.62 barrel. The result however wasn't increased accuracy. Infact mini 30's are notoriously less accurate than their mini 14 brothers.... I don't see why squishing bullet would make it more accurate...

I don't see why somebody'd pay $700 for a mini, when they could just cut the bull and buy a good AR.

I like the looks of the ruger mini's, and I'd gladly own one if somebody gave one to me, but otherwise...

back on topic. I don't know. My guess is its magic.

[Bessy]

I had heard ruger tapered the barrel on their mini 30's, basically forcing a Russian 7.62 (usually around .311 or 3.12) down a nato 7.62 barrel. The result however wasn't increased accuracy. Infact mini 30's are notoriously less accurate than their mini 14 brothers.... I don't see why squishing bullet would make it more accurate...

I don't see why somebody'd pay $700 for a mini, when they could just cut the bull and buy a good AR.

I like the looks of the ruger mini's, and I'd gladly own one if somebody gave one to me, but otherwise...

back on topic. I don't know. My guess is its magic.

EJSG, I'm with you buddy.

[ironfoot]

http://www.grantcunningham.com/acc-rifle.html

"In the late 1970s, I did a three part series on the Python for American Handgunner magazine that involved days at the factory debriefing the engineers. They told me that Python bores were tapered by .001" toward the muzzle, to drive the bullet deeper into the rifling. This is, if you think about it, quite a feat of engineering. It may be one reason why for so many years, people who preferred other revolvers paid gunsmiths to install Python barrels on them, creating a "Smolt" when the tube was joined to an S&W and a "Cougar' when mated to a Ruger."

So, not magic, but quite a feat of engineering.
Wish the article said how.