I had a student at the range shooting an older Sig P220 in .45 ACP. On his fifth shot from a fully-loaded 7-round mag the slide would lock back almost every time.
Inspection revealed the top cartridge was not hung up or depressed in any way. It appeared that the slide lock was simply engaging each time, and either depressing the slide lock or retracting the slide chambered the top round each time. The last two rounds fed fine.
At first I thought the student may have been hitting the slide lock with his thumbs, but I ruled this out by observing him. It also happened only on the fifth round, which I found pretty odd. The phenomenon happened with two different mags, both of which were in fine condition.
I field stripped the gun and saw absolutely nothing wrong. The gun was relatively clean, and properly lubed.
Ammo was a handload using 230 grain cast RNL at about 800 fps that has a flawless track record.
Any insight into potential causes of the malfunction would be greatly appreciated.
Inspection revealed the top cartridge was not hung up or depressed in any way. It appeared that the slide lock was simply engaging each time, and either depressing the slide lock or retracting the slide chambered the top round each time. The last two rounds fed fine.
At first I thought the student may have been hitting the slide lock with his thumbs, but I ruled this out by observing him. It also happened only on the fifth round, which I found pretty odd. The phenomenon happened with two different mags, both of which were in fine condition.
I field stripped the gun and saw absolutely nothing wrong. The gun was relatively clean, and properly lubed.
Ammo was a handload using 230 grain cast RNL at about 800 fps that has a flawless track record.
Any insight into potential causes of the malfunction would be greatly appreciated.