S&W 686 locked up shooting blanks

[MR.G]

After replacing the mainspring in my S&W 686 today I wanted to test it. There wasn't a convenient place to shoot live ammunition, so I used a bullet puller to make some blanks out of loaded ammunition. When firing the shells, with primers only, the gun locked up after almost every shot. Had to remove the fired shell so that the cylinder would rotate again. Is there a reason why this would happen?

 

[Sgt127]

Normal. The primers will push back out of the primer pockets into the breech face/firing pin hole. Without the full charge of the round going off, to "press" the primer flat again, its likely to jam up. Its freaked me out before.

 

[MR.G]

Thanks. I have done this before to test revolvers and never had it happen.