My newly purchased full size 9mm does not want to always chamber the last round. Thought it might be a mag problem but they all work well in my friends M&P. Different ammo, no difference. Most of the malfunctions seem like its not fully going into battery. %95 of the time its the last round. I only have about 150 rounds through it so far so do you think its a break-in issue?

My first question is always "Did you thoroughly clean the gun and lube per the factory manual?"
If not, that is where to start.

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Science plus Art

If the pick up rail is passing over the last round so that you end up with the slide closed on an empty chamber, then the last round is not getting topside in time and that may mean a weak magazine spring.

If the pick up rail is pushing that round out of the mag, but it is hanging up on the feed ramp (this is what it sounds like from your description), then you have an issue with the ramp, the chamber or something else and S&W needs to have a look at it on their dime. Call them and describe the problem and nicely ask for a shipping label. This is not a lube or cleaning or break-in issue.