Was considering converting my m&p 40 to 9.mm, I already have a .357 Sig barrel for it and am pleased with the results.
I am interested in a Storm lake extended barrel (4.95 inch) , with ports, does a ported barrel offer any advantages over non ported ?
Also is a S&W 9mm magazine compatible with the conversion ?
Thanks

You are kidding us all with this post right?

The advantage of the ports is decreased muzzle rise.

Personally I think the disadvantages (extra barrel length and fireball from top of gun) outweigh any advantages.

Since the mp 40 and 9 use the same frame, mp9 mags are a go in a converted 40.

Hope that helps

The ported barrel will allow for less muzzle climb. The 9mm magazine will work in a M&P40 with 9mm barrel.

I have the Storm Lake regular 9mm conversion barrel along with the SW. 40 & .357sig. I don't know how the ported barrel will work, but the 9mm works great. I took a moving targets class with it, went through 250 rounds and it functioned perfectly. I have put a few hundred more through it since without any problems. Yes the 9mm magazines work in the .40 frame.

9 mm handguns are not that expensive that I would deviate from factory to covert something else to get one, but then I am not a tinkerer. It seems for some, that firearms are kind of like adult Legos. Good luck!

You can also just reload the 357 sig to 9mm performance. No need to change /buy anything to accomplish that. I do it with my M&P40 Pro now.
The savings on the barrel and mags will just about pay for the press if you need one.

__________________
Dave

Good idea I reload and will give it a try
Thanks all for the replys

A 180g bullet loaded to about 700 fps gives equivalent recoil to a 115g 9mm bullet close to 1100 fps. On my M&P 40/9, I've run both loads (40 and 9) and they really do feel the same so that is a good comparison if you want to know what a 9mm load would feel like in a 40 gun.

That being said, the M&P 40 slide is slightly heavier than the M&P 9 slide and 9mm loads will not eject with the same authority out of this gun compared to a real M&P 9. While the 9 and light 40 loads do cycle reliably and lock the slide back, the cases fly up only 1/2 to 1 foot up and often land on my arms, head and forehead. I need at least 1100 fps out of a 120g bullet for the cases to eject with authority in this gun. I don't care about getting max velocity for any ego sake, just enough to not be annoyed by having hot cases land on me while shooting. A reduced recoil spring would help, but then you have to deal with a weaker slide closure so I don't want to try that.

IMO, no need for any porting on a 9mm barrel, the load has such low recoil and flip already and having a firework show in your sights won't help. Just a plain 9mm barrel with 9mm mags will work fine.

I would like to hear more about the moving target class.

Just order a Storm Lake 357 sig barrel for my 40c already have the 9mm conversion barrel for it .. and bought a couple of 9mm mags for it .. The 9mm barrel shoots as well as the stock 40 barrel ..

does yours shoot the 357 sig as well as the stock barrel is it to POA??

I am using a KKM barrel poa is about the same
have to compensate a little due to the increased
velocity. I shoot mostly at 15 yards.