Hi, I have a new M&P-9. It came with a range kit. It has three magazines, which are stamped 10 on the side. However, I can't get ten rounds into these magazines, they stop loading at nine rounds, can't force the tenth round in.
They will fit 10, but it is a very tight fit because the laws creating the 10 round magazine limit are unforgiving. If you can force in an 11th round, it is a criminal violation. The easier it is to get the 10th round in, the more likely it is that an 11th round can be forced in, creating a big problem for everyone concerned. Since you live in Massachusetts, I suggest you either: (1) get a magazine loading tool such as the Uplula; or, (2) move to a free state.
As your mag spring stays fully compressed for some time (as fully loaded as you can get it), the spring will compress better. Cycling also softens a new stiff spring, so shoot a bunch of 9 strings, then force #10 in there and continue shooting. Leave the mags loaded between range sessions. They will loosen up.
I live in CT, same deal with the 10rd... I I both a shield and a 2.0. I bought a maglula and loaded all 7 of my magazines fully and let them sit. I can now load them by hand, even the last round. I would suggest you do the same.
9mm magazine issue
Linear Mode
