Winchester factory ammo (.223) problem

[LanceS4803]

As my reloading setup is still packed in boxes from the move, I bought a box of Winchester's Match .223 ammo, with 69gr Sierra MatchKing bullets.
Shooting out of my S&W M&P, when I charge the cartridge, it sets back the bullet in the case mouth. So, I put the round in the chamber and then slowly close the bolt. The problem is, when the next round is chambered, I get the same setback. And the very likelyhood of a compressed load.
I thought about just crimping the cartridges tighter, but think this should be something Winchester should know about.
Correct?

 

[DaveB]

I also own a S&W M&P 223. Do not know if we are having the same problem-will be following this thread and will check the rifle once I return from Buffalo.

 

[MUP]

Definitely contact Winchester.