I am having the same (almost exact) issues as outflyin. 1st range session 150 rounds Speer ball - 1 FTF dismissed as break in issue. 2nd range session (cleaned & lubed) 150 rounds Speer ball - numerous FTF always the second round in the magazine. 3rd range session (cleaned and lubed again plus all magazines disassembled and cleaned but not lubed) 150 rounds Speer ball with numerous FTF of the second round in magazine. FTF's occurred across 4 different 6 round magazines. It was sent back to S&W (told not to send the magazines by CS rep). Returned about 10 days later. Paperwork said the locking block and RSA was replaced the the gun test fired. Took it to the range and it continued to have FTF's. Tried both ball and WW Ranger 230 JHP. The rounds appear to be nosediving and catching at the bottom edge of the locking block. Pulling the slide fully rearward and releasing chambers the round.

Shot a friend's Shield 45 last week. Every round chambered and fired without any type of malfunction.

Discussed the problem with an armorer friend who suggested locking the slide back and fully loading the magazines and leaving them sit for two weeks. It has been two weeks and I will shoot it again this week. I will bring my friend along with his Shield. If it FTF I will have my friend shoot it. I will also try his magazines in my Shield. If it has FTF's it will go back to S&W.