Let your fingers do the walking, call them
https://www.littleskeeters.com/skeeters-history/Thus began the quest for a material that would resist distortion and provide a tube that would function at a level that would make it practical for everyday use. I then turned to a friend, Leonard Vallender, President of FenBar Precision Machinists, Inc., a superb precision machinist and engineer who as a shooter was very interested in the potential of the product – although having doubts about the concept. Soon after machining the tubes in aluminum and test firing them, he was as convinced as I was that the patterns were on the money but that the distortion of the tubes and bulging of the ammunition was a concern.
After months of trial and error, we came upon the right combination of materials, size tolerances and internal and external dimensions that would be universally acceptable to all guns – knowing that chamber size varied from gun to gun. We have theorized that as the shot column enters the larger diameter bore, the shot column shortens so that when the shot column exits the barrel very few pellets pass from the rear of the column causing less disturbance or turbulence. Our patterns displayed no flyers, which attest to our theory.