Apex Brings a 40/9 Conversion Barrel To Market For M&P Owners

Much to the elation of M&P 40 police trade in guns like myself, Apex has released a conversion barrel that allows you to shoot 9mm. With the new M&P 2.0 being released this is a well-timed product launch because I imagine that many police departments that are still running the M&P 40 will likely trade them in towards the new and improved 2.0.

In their press release, Apex covers some reasonably impressive specs like the availability of a Gunsmith fit barrel for shooters that are looking to squeeze every ounce of accuracy out of their converted gun as well as a drop-in barrel for the casual shooter that is content with a 1.5″ group at 25 yards. The Gunsmith fit barrel is claimed to offer a one inch or better group at 25 yards, more than enough to outshoot 99.9% of shooters out there.

They do say this about barrel accuracy, though:

Final accuracy results after installation may vary based on the individual shooter’s ability, ammunition selection and variations in factory firearm tolerances. Additionally, as with all conversion barrels, the shooter may experience erratic ejection patterns due to light or low velocity rounds.

On top of the two fitment options, Apex is also offering a 5″ barrel as well as a 4.25″ barrel covering every M&P with the exception of the Compact (and I suspect that a Compact solution is not far off depending on what they hear from customers.) It also appears that there is no need to swap springs or anything else when converting the pistol but I couldn’t find anything concrete on their website.

You can see the full line of Apex Grade Conversion Barrels for M&P over at their website. Currently, the MSRP on the conversion barrels is set at $199.95.

Patrick R

Patrick is a Senior Writer for The Firearm Blog and TFBTV Host. He likes guns and has liked shooting guns for as long as he can remember. You can follow Patrick on Instagram @tfbpatrick, Facebook, or contact him by email at TFBpatrick@gmail.com.

The above post is my opinion and does not reflect the views of any company or organization.


  • Andy

    Cost of police trade in + $199, isn’t that fairly close to just buying a brand new M&P in 9mm? My LGS has 9mm M&P for $369.

    • Just say’n

      Yup, my thoughts exactly. Plus you likely have a well-used gun on your hands.
      Just buy new and be done with it.

  • Wang Chung Tonight

    Will the M&P .40 magazines feed 9mm reliably??

    • Patrick R. – Senior Writer

      Probably not.

      • Hinermad

        Agreed. I researched doing the conversion on my M&P 40 Compact and just about every account I found of someone who tried it said the .40 S&W magazines just wouldn’t feed 9mm reliably. So I got a handful of new magazines along with the new barrel.

        Also, I didn’t find it necessary to change any springs, so the Apex conversion probably won’t need new ones either.

      • Joel Thompson

        I have the storm lake conversion barrel for my M&P40c, and one day I left my 9mm magazines at home and tried using my 40 mags. Every once in awhile I would have an issue a 9mm round proud ingredients from the top of the feed lips, but otherwise they seemed to function fine. I wouldn’t carry it with .40 mags, but they’ll do in a pinch at the range.

    • jonp

      Not from what I have read. 40 will feed 357Sig fine with a barrel of course but to use 9mm you need new magazines. I saw some on sale today for $17

  • Wingnut

    Now, one for the shield please?

  • Hoplopfheil

    Hideous branding. They should make these barrels for the Honor Guard instead of the S&W. Oh wait, same thing. 😉

  • Geoff Timm

    I seen prices over the counter in NE FL for police surplus .40 S&W for around $400, toss in another $200 and you might as well buy a new Walther, H&K, or SIG. Geoff Who is frugal.

  • Joel Thompson

    Or you could buy a Storm Lake barrel that has been out for a few years. I picked up one for my new compact for $165.

  • DJ9r

    If the drop-in/no-fitting-required barrels actually shoot 1.5″ groups at 25 yards in average pistols on a regular basis, that will be impressive.

    And what’s up with the opening line of the article being worded as if the pistol was the writer? Waaay too confusing before my second cup of coffee this morning…

  • dltaylor51

    I have a M&P shield in 45acp and its already the most accurate 45 I have ever fired,my friend also has one and he says the same thing.I see no need to spend money for improvement because there is not that much to improve on.

  • BeoBear

    Or you could buy one from any of the other manfacturers offering the same thing…………….

  • jonp

    Odd as I was just looking at this today as I bought one used for $320 last week. Apparently you can use the 9mm as a direct swap with the 40 barrel and just need a new 40cal magazine. The 40cal can be swapped with a 357Sig barrel and no new magazine is needed, the 40cal magazine will work with it. There are several companies making these barrels like Storm Lake, KKM etc. Some also say you can use a S&W barrel and that costs about $75 but is not as accurate.