15 round fnx 40
I just left bass pro a few minutes ago and saw 15+1 round fnx 40 and i thought it was a mistake. I am a little upset since i just bought a new fnx 40 2 weeks ago and it only came with 3 14 round mags and its a new gun i didnt buy it from bass pro but still. I know one more round is not a big deal but i could need that one extra some day .Warning, modify your gun at your own risk.
I was at the store a few months back checking out a S&W M&P 40. One thing of note, the magazine held 15 rounds with the same exact length magazine.
Today, I did some investigating and discovered that not only were the followers roughly the same dimensions, but both also had the same lockplate thickness.
I kept examining the differences to figure out why the M&P could hold 15 rounds while the FNX could only hold 14.
I compared the length of the springs next. I found the M&P's springs to be significantly shorter. One simple way to do the conversion is to simply purchase the M&P spring and make it work in the FNX.
I decided instead to alter my current spring.
I counted the coils and compared the angles. The angles of the springs were pretty much the same. However, the FNX had 13 coils, while the M&P has only 11. I clipped the bottom of the magazine spring, so as to enable the smaller portion of the top to still be able to collapse inside the larger coils. This is how the M&P spring is constructed.
Upon doing this, I then bent the leading edge of the coil back to become parallel with the adjacent wire, and bent the hook inward in the middle. (pictures will be posted next)
I then reassembled and loaded up the magazine, easily fitting the 15th round inside the magazine.
I then proceeded to test.
I cycled the weapon with live rounds in the magazine (pointed in a safe direction with safety on) as fast as I could to try and emulate actually firing it. All rounds fed. All rounds went into chamber and were extracted. There was still plenty of pressure pushing out the last round. The slide still locked back.
I will be conducting a live fire test with the pistol this weekend to determine if there are any reliability issues. Once I am finished, I will be converting the rest of my magazines also if all goes well. Why should FNX 45 users get 15 rounds while FNX 40 users only get 14? Phooey I say.
If there are any issues with my current alteration, I will be testing the M&P magazine next.