Just Curious

[warrumr]

I'm going to be purchasing a Smith & Wesson M&P chambered in 9mm. If I want a different caliber could I just change the barrel and the magazines or would I have to replace internal parts? My brother said he thinks in the glocks you can change just the barrel and the magazines but he isn't sure so I was just curious and ask. Thanks for the replies.

 

[Tactically Fat]

You can...in theory.

If you want to change calibers, it's best to start with a "larger caliber" then exchange downward.

Reason: There may be an issue with the fitment of the muzzle of the barrel through the hole in the slide. Larger calibers will generally also have a larger outside diameter (OD) of the barrel.

If the OD of the 9mm is "tight" to the slide then it's possible that the OD of a .40 S&W barrel will be too much.

Also, IIRC, aftermarket barrels for Glock are manufactured so that the OD is the same as the OD of the factory original - so there's no "slop" or "play" between the barrel/slide interface.

That said - I don't know for SURE if this is how M&Ps operate...but I suspect so.

 

[chezuki]

You can...in theory.

If you want to change calibers, it's best to start with a "larger caliber" then exchange downward.

Reason: There may be an issue with the fitment of the muzzle of the barrel through the hole in the slide. Larger calibers will generally also have a larger outside diameter (OD) of the barrel.

If the OD of the 9mm is "tight" to the slide then it's possible that the OD of a .40 S&W barrel will be too much.

Also, IIRC, aftermarket barrels for Glock are manufactured so that the OD is the same as the OD of the factory original - so there's no "slop" or "play" between the barrel/slide interface.

That said - I don't know for SURE if this is how M&Ps operate...but I suspect so.

Close, the barrel OD's are virtually the same between 9 & .40. It's actually the top of the breech that is different on the M&P's. You can put a 9mm barrel in a .40 slide and there will be slight play around the load-chambered indicator port. A .40 barrel in a 9mm slide won't lock-up.

 

[warrumr]

Ok thanks guys

 

[Tactically Fat]

Yeah, after I posted I was also thinking about the differences in the chamber hood portions of the barrels.

Still stands: Buy the "bigger" caliber - convert down. Unless it's .45...then you're stuck pretty much with .45.

And buy a proper CONVERSION barrel. Not just a barrel in the caliber you want. The proper conversion barrels will have the same OD that you need for proper lock-up and function.

 

[chezuki]

Yeah, after I posted I was also thinking about the differences in the chamber hood portions of the barrels.

Still stands: Buy the "bigger" caliber - convert down. Unless it's .45...then you're stuck pretty much with .45.

And buy a proper CONVERSION barrel. Not just a barrel in the caliber you want. The proper conversion barrels will have the same OD that you need for proper lock-up and function.

No conversion barrel needed for M&Ps. Just use a stock 9mm barrel in the .40 slide. You're mixing Glock info...

 

[Tactically Fat]

No conversion barrel needed for M&Ps. Just use a stock 9mm barrel in the .40 slide. You're mixing Glock info...

Probably. I'm not very bright. :-(

 

[warrumr]

I don't think I'm going to switch calibers. If I want a different caliber I would probably just buy a gun in a different caliber. The thought popped in my head earlier so I just thought I would ask. Thanks for the info. I will let my brother know since he didn't know either.

 

[throttletony]

I don't think I'm going to switch calibers. If I want a different caliber I would probably just buy a gun in a different caliber. The thought popped in my head earlier so I just thought I would ask. Thanks for the info. I will let my brother know since he didn't know either.

Having a dedicated gun (where budget allows) is preferable by far! With limited space, limited number of guns, ammo shortages, etc. swapping barrels might seem more appealing.
I would much rather have a dedicated second gun if possible. Heck, I know quite a few guys who like to have a complete backup of their main gun should the need arise (parts, back-up, hand one to a buddy/spouse in an emergency and not worry about mixing the wrong calibers/magazines, etc.)
2 is 1, and 1 is none--- or so they say

 

[throttletony]

Close, the barrel OD's are virtually the same between 9 & .40. It's actually the top of the breech that is different on the M&P's. You can put a 9mm barrel in a .40 slide and there will be slight play around the load-chambered indicator port. A .40 barrel in a 9mm slide won't lock-up.

Thanks for posting this. I was unaware of that difference.
It sounds like it is still safe to shoot though? Or are there any unsupported areas that would need to be supported? Does it ever freeze up, not go into battery, etc?

 

[chezuki]

Thanks for posting this. I was unaware of that difference.
It sounds like it is still safe to shoot though? Or are there any unsupported areas that would need to be supported? Does it ever freeze up, not go into battery, etc?

The 9 barrel works fine in the .40 slide, though there's likely a negligible (for most shooters) decrease in accuracy due to the .026 of wiggle room. The .40 barrel won't fit in the 9mm slide.

 

[venenoindy]

in the real world there is no significant difference in performance between handgun calibers that is worth all the trouble, if you have a preference on a certain caliber just stick to that and invest money on ammo because if you can't afford to practice I think is pointless to have a caliber that you can not practice with. I stick to 9mm since I can shoot the most and practice more what counts is rounds on target.

 

[BugI02]

I think I would get a 357 sig conversion barrel for a .40 just so I could shoot 357 occasionally, as the functionality is so similar (say an EFK barrel for my FNP40). Anything else +1 on dedicated guns. Have daydreamed about 9x23 but too many worms in that can!