Conclusions

A finite difference computer simulation of rifle barrel vibrations was developed from first principles. A model of realistic pressure initiators of vibration was incorporated into the model to give proper weighting of vibration sources. The model produced good agreement with classical vibrational mode solutions representing non-transient mode shapes. The transient results of the model were reasonable and yielded valuable insight into the design of barrel modifications.

The prototype rifle and barrel now are being built, which will provide the measurements that will validate this model. The most significant realization should be small, tight bullet groups across a range of loads and temperatures (which affects internal ballistics), with no adjustments required on the part of the shooter.

Figure 5a. Vibrational Response, No Modification. Snapshot in Time Just as Bullet Exits Barrel.

References

ADC, Inc. 1996. PC Bullet for Windows, Software for Shooters, software sold and licensed by ADC, Inc., Scappoose, OR, copyright 1989-96.

Brmel, Hartmut G. 1996. QuickLOAD Interior Ballistics Program and QuickTARGET Exterior Ballistics Program, commercial software sold and licensed by the author, D-63303 Dreieich, Germany, copyright 1996.

Carnahan, Bryce; H. A. Luther; and James O. Wilkes. 1969. Applied Numerical Methods, John Wiley & Sons, New York, p. 451.

Harris, Cyril M., and C. E. Crede. 1976. Shock and Vibration Handbook, Second Edition, McGraw-Hill Book Company, New York, p. 9-5.

Press, William H.; Saul A. Teukolsky; William T. Vetterling; and Brian P. Flannery. 1992. Numerical Recipes in Fortran 77, Second Edition, The Art of Scientific Computing, Cambridge University Press, p. 490-551.

Biography

Dr. Schwinkendorf earned his B.S. and M.S. degrees from Oregon State University in 1981 and 1983, respectively, and his Ph.D. from the University of Washington in 1996, all in nuclear engineering. His doctoral work was in the field of severe nuclear reactor accident simulation. Dr. Schwinkendorf has worked as a reactor physicist and nuclear criticality safety engineer at the Hanford Site in southeastern Washington state since 1983.

Mr. Roblyer received his B.S. in physics from the University of Oregon and M.S. in nuclear engineering from the University of Washington, and has worked in the field of vibration control engineering, specifically vibration and signature analysis of rotating machinery, at the Hanford N Reactor.

Both Dr. Schwinkendorf and Mr. Roblyer share an interest in the shooting sports and have jointly applied for a patent on the rifle barrel vibration control system described in this paper. Three Rivers Technologies was formed by the authors to develop this system.

**This paper was reprinted with the permission of Society for Computer Simulation, and was first presented at the 1998 Advanced Simulation Technologies Conference (ASTC '98), April 5-9, 1998. SCS supports multiple conferences, or tracks, at these meetings, and the one we presented to was Military, Government and Aerospace Simulation. This paper appears on page 66 of the Proceedings.