Originally Posted by
JonInWA
Results from shooting an IDPA match on Saturday. First, I fired a cylinder comprised of 2 Winchester Silvertip JHP, 2 Federal Hydrashok JHP, and 2 Fiocchi SJHP; I immediately had one primer failure to detonate with one of the Winchester Silvertips, all others were fine. The GP100 is equipped with an OEM brand new Ruger mainspring, and a brand new ISMI trigger revound/triggerguard latch spring. Based on repeated issues with the Silvdertips encountered with a 12# ISMI mainspring, a 12# Wolff mainspring, and a 14# Ruger mainspring, I have raised the issue with Olin Winchester, and, until satisfactorily resolved I have removed the Silvertips from duty/EDC/defensive carry in the GP100. there are clearly some ongoing primer issues going on. Federal 158 gr HydraShoks will be used for all defensive/duty uses (which isn't a bad way to go, but the Silvertips really have a steller reputation. But at this point, I can't justify using them, or in good faith recommending them. We'll see what Olin Winchester says.
Am experienced and skilled reloader and personal friend of mine provided me with 100 rounds of relaoded ammunition that he had personally crafted to my specifications-SJHP 158 gr bullets, with a muzzle velocity of 1000 fps. CCi 550 primers, 12.45 IMR 4227 powder, Norma and Aquila cases used. While the accuracy and recoil impulse was superb, some problems immediately developed; after one cylinderful was fired, reloads required thumbpressing into the chambers to seat, and even that was not sufficient, and difficulties in closing the cylinder and if closed, cylinder rotation problems were experienced. Several light srtikes were experienced as well.
The closing and binding issues were resolved by brushing the ejection star (both front and back) and the rear of the cylinder itself. I also boresnaked out each chamber, but that was probably unnecessary; vigerous brushing of the ejection star, ejection axle supporting the ejection star, and the rear cylinder face satisfactorily resolved the issue(s)-both with the handloaded cartridges, and subsequently with Magtech 158 gr flat-nosed lead Cowboy cartridges.
I'm thinking that a combination of GSR accumulation at the back of the cyllinder and on the face of the ejector star are causing the issues; I'm also ensuring that the ejection rod axle, ejection star, cylinder ejector guide pins and cylinder back are dry and without any oil or cleanser residue that would serve as an attractant for GSR.
After the match, both fired cases and unfired cartridges (and control factory cartridges) were carefully measures in all dimensions, as were the cylinder charge holes; all were within allowable specifications, reinforcing our suspiscions that the issues were caused by GSR residue and accumulation. I'm not concerned with factory ammunition, as the cylinder closing, binding and heavy triggerpull issues were only experienced with the reloaded cartridges.
For now, both my load and unload protocols with these cartridges will be with ejector star/rear cylinder toothbrushing bith prior to loading and subsequent to scenario firing. as part of the "unload and show clear" process. My reloader may also swiotch to another propellant powder.
Thoughts, critiques and recommendations welcome. Oh, and in the last stage of the day, we had heavy, driving rain. Operationally it presented no issues; I continue to be impressed with the VZ black G10 Twister grips
Best, Jon