Todd Jarrett Wins \\World Shoot X - uspsa

y Guy Neill, RELOADING EXPERTVILL 0\RELOADING• .40 S&W CASE SEPARA.TIONSMany shooters are currentlyshooting the .40 S&W cartridgeloaded with 200 grain bulletsand a fast-burning powder. It isclaimed that this gives you lessfelt recoil than other loadingsfor the cartridge and, if that'sthe way it feels for you, then itis the way to go. Or is it?The folks at Image Industries,makers of the Case-Pro100, have brought to my attentiona possible problem withthis load. The problem theyhave seen includes extractorgrooves collapsing and totalcase/head separations. Themystery here is that there wereno warnings or signs prior tothe problem.When I was originally advisedof this, it concerned a specificbrand of case. Since then ithas proven not to be confined toa specific manufacturer. If ithad been confined to onemaker, the problem could easilybe determined to be a problemwith the cases. Since this is notso, it is of greater concern.This problem manifests itselfafter about a half-dozen firings.This should rule out brassfatigue because of the low numberof cycles. Pressure testsmade with the same load revealedpressures averaging inthe neighborhood of 41,000 psi,but they did not have a widerange of values. With the combinationof a relatively smallcase, a fast powder and a heavybullet, such variations would beexpected.An engineer who was involvedwith the original developmentof the .40 S&W statedthat it would take pressures inthe vicinity of 80,000 to 85,000psi to collapse the groove. Thetests showed that we don't havethat sort of pressure here. Wedo have a pressure that willplace the brass in a yield zone,depending on the exact hardnessof the case. I have not yetobtained hardness values forthe cases, but I suspect that theanswer to the question of whatLosing the Equipment Race??Don't let your equipment hold you back. Let Itrazos Custom gunwork,racceierateyour performance with one of these custom gun packages:Single stack guns:Match BarrelTighten slide to frame fitTrigger jobTriggerHammerSearBeavertail grip safetyWide extended safetyBomar Lo-Mount sightsGuide rodReplace all springsEjector/Extractor tuningMagwell$795.00High capacity guns:Schuemann ramped bull barrelTighten slide to frame fitTrigger jobTriggerHammerSearBeavertail grip safetyWide extended safetyBomar Lo-Mount sightsReverse plug guide roclAll springs & pinsEjector/Extractor tuningAll parts to complete frame/slide$995.00Prices include all parts, labor, and shipping on your frame and slide.Call for prices on other packages tailored to meet your individual needs.Brazos Custom GunworksBob Londrigan - PistolsmithRt. 1 Box 740, Morgan TX 76671 817-622-2245is causing this problem involveswork-hardening.A factor of the stress involvedis the diameter of thecase. While the .40 operates atthe same pressure as the 9mmLuger (in factory loadings), thestresses in the case are greaterbecause of the larger diameterof the case. My theory, and thatis all it is at present, is that thework-hardening of the firingresizingcycle for the stress involvedat these pressures resultsin a case that is too hardafter a small number of firings.RELOADING continued on page 54.March/April 1997 Page 5