Taran tactical +6 m&p extension?

[greene]

Just got a +6 for a 9mm m&p, problem is I can only get an extra 5 in it. This is with new & used mags. Anyone else have this issue? Do they require any break in to fit to capacity? Thank you

[Spiffums]

Did they come with a new spring?

[greene]

Yes sir.

[erik18]

I had no issues getting an extra 6 rounds into mine even when the springs were brand new.