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Think about the firing pin on aSmith & Wesson revolver. It willreach only so far. If the primer is notwithin the area it reaches, there willbe poor ignition reliability.The industry standard dimensionsfor a small pistol (or rifle)primer specifies a height of 0.115inch to 0.125 inch. The primerpocket is, correspondingly, definedas ranging from 0.117 inch to 0.123inch. A 0.125-inch-high primer in ahole only 0.123 inch deep does notappear to be a really good situationto me, but it can occur at the extremesof the tolerances.Primers are built with an explosivecalled lead styphnate, which issensitive to impact. Hit it with theright amount of force and it willdetonate. This is what is desiredwhen the firing pin hits the primer,but a primer sticking up above thecase and having the breechface ofthe gun slam into it can produce thesame result. Therefore, it is a safetyconsideration to ensure the primer isbelow flush with the case.I have also seen malfunctionscaused by high primers. As the cartridgecame up the breechface of thegun (1911-pattern gun), the protrudingprimer snagged on the firing pintunnel opening in the breechfaceand stopped further chambering ofthe round. No detonation of theprimer occurred, but the thoughthas to be that it is riding on the edgeof firing out of battery. As it stands,it would still cost time to clear it ina match.If you measure the depth of yourprimer pockets and find them to betoo shallow for the height of theprimer, they will require "uniforming."Several companies makeprimer pocket uniforming tools, but,like case trimming, it is a time-consumingtask if a large quantity is beingprocessed. If the primer pocketsare too deep, the cases are scrap.Different presses have a different"feel" when seating primers. Withgood feel, reliable priming is relativelyeasy. Without feel, and if thereis no positive seating stop, the con-dition of the primer is mostly aguess.Regardless of the machine usedto prime the cases, it is a good ideato develop the habit of inspectingthe primer seating on each cartridge.With a progressive loader, this mustbe done after loading the ammunition.With other presses, the primingquality can be inspected immediatelyupon removing the case fromthe priming tool, whether it is aloading press or specialized tool.Given some practice, most peoplecan develop the ability to slide thetip of their index finger over theprimer and determine if the seatingis satisfactory.Many competitors try eachround they load in either a chambergauge or the barrel of their gun (outsidethe gun). It would be very easyto check the primer seating whiledoing this. If you do not check yourammunition in this manner, youshould still examine each roundeither as you prepare to put it intoboxes or magazines.Hammered a Course o Fire Lateiy?We sold a few of ourtop-of-the-line Tack Driversto the US Army IPSC Team!•You may already know usfrom the gun parts we manufacture.Our innovative ideas for partscome from years of experiencebuilding custom guns like these.•At Evolution Gun Workswe build top quality toolsfor the competitive shooter.PHONE 215-348-989'2 • FAX 215-348-10564050 B-8 SKYRON DRIVE • DOYLESTOWN PA 18901US ARMY IPS( TEAM GUNS52 FRONT SIGHT • May/June 1998