View Full Version : Question for mr. Calfee

Albert B
01-29-2008, 09:23 AM
Sir, I follow the discussions on barrel harmonics and tuners closely. A fundamental question came to my mind: When you select a barrel for a rifle/cartridge combination (for example a smallbore rifle), how do you determine the combination of diameter and length of the barrel? Is this done by trial and error, is a 'rule of thumb' used, a calculation or some other method?
Any comments will be greatly apreciated.

Albert B
(The Netherlands)

01-31-2008, 08:39 AM
Friend Albert B:

I quote from you: "how do you determine the combination of diameter and length of the barrel? Is this done by trial and error, is a 'rule of thumb' used,"

My friend, you've asked an excellent question......please give me a little time and I'll give you an answer.....

In the mean time, I will leave you with this thought.......our barrel blank will tell us where it wants to be chambered and crowned.......to produce killer accuracy, we must listen.

Your friend, Bill Calfee

Big Al
01-31-2008, 02:28 PM
I just finished reading the review of a book and like any information that brings answers to questions that are not in debate, I always feel they have a little higher value. The book in question is this one.

Random Shots:
Episodes in the Life of a Weapons Developer

by Roy E. Rayle

In this book the author discusses the fact that by clamping barrels together on the Vulcan cannon they greatly reduced the dispersion of shots. The same applies with the M-134 mini-gun.

This brought into mind the R&D project of the late 60's early 70's at the GE proving grounds. At the time there was development of a weapon similar to the-134 going on. This system used the 5.56 NATO and the high rate of fire was brought up to 17,000 rounds per minute. One of the major problems was shot dispersion. A new and mush stronger clamping devise was devised and brought the problem under good control. These barrels are vary thin. They are contained by a half lock in the rotor housing and are clamped on the end to keep thin from flying a part, due to centrifugal force.

The thing about this that really rang for me was the stronger the clamping action of the muzzle the better or smaller the shot dispersion.

After reading this marvelous book for some number of pages, It made for a lot of new questions, and answered others to my mind. I now have a little better understanding on why the stopping of the muzzle has the effect it does with a tuner.:D

My hats off to you Mr. Calfee for your posts, it got me to search for answers that I've have seen first hand but did not recognize for what they are.:)

02-06-2008, 08:23 AM
Friend Albert:

Some thoughts have been placed on my website for you.


Click on "Potpoutti"

Your friend, Bill Calfee