Mp9 magazine California

MyMP9 · #1 09-04-2013, 10:13 PM

Hello everyone,

I am a new owner of the sw mp9 in CA. I am new to firearms and currently getting to know my gun in terms of its functionality. My question is if my 10 round magazine is 9 plus 1. I tried loading 10 rounds without having the slide pulled back and it would not accept the mag.

Why do some firearms display their magazines as 10 round mag or with plus one?

Can someone please clarify for me?

macski222 · #2 09-05-2013, 01:09 AM

Your mag holds 10, the +1 is the one in the chamber. Don't be afraid to give the magazine a little love tap to get it to lock in. The search function on this site is your friend, there are many threads on this type of thing. Living in MA I also have 10 round mags and one thing that I did to make my mags accept 10 rounds/get the magazine to seat in the gun easier, was take mags apart and sand down the plastic mag follower so that the arches aren't so pronounced... Giving you more space to work with in the magazine. Again, do some looking around on here or YouTube for more on this little modification. It'll be worth it, and make things less of a hassle

MyMP9 · #3 09-05-2013, 02:53 AM

My gun is brand new. It was picked up a few days ago. I read that the spring in the magazine needs to set with it being fully loaded. Is this true?

I loaded 10 rounds in my mag and it wouldn't catch even with a good tap.

thanks again.

Hillbilly77 · #4 09-05-2013, 03:09 AM

Quote:

Originally Posted by MyMP9

My gun is brand new. It was picked up a few days ago. I read that the spring in the magazine needs to set with it being fully loaded. Is this true?

I loaded 10 rounds in my mag and it wouldn't catch even with a good tap.

thanks again.

Take the magazines apart and trim the follower legs down with either a file or a razor blade. Remove about 1/8" to start with, then go from there.

Here is a thread I posted when I had the same problem.
**UPDATE IN POST 5 - FOUND A FIX** M&P9c Magazine 10 round fit question

Rastoff · #5 09-05-2013, 05:35 PM

Quote:

Originally Posted by MyMP9

I read that the spring in the magazine needs to set with it being fully loaded. Is this true?

No, this is a myth. Leaving the mag loaded for a period of time will not make it easier to load or insert in the gun easier.

While mine will seat a loaded mag with the slide closed, I don't do that. I never use any of my guns in the +1 state. That extra round is really not necessary. So, insert the mag with the slide locked back. Drop the slide and press on with whatever you're doing.