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Conversion Barrel for M&P

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Mar 13, 2009
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Preface: This is a small "review" of the conversion barrel I bought for my M&P40. I am only writing this, because if I saw this before I ordered the barrel I would have made my decision a lot sooner.

I am the proud owner of an M&P 40 (yes PROUD, I love the gun). With the ammo supply issues not getting any better I decided to look into a conversion barrel so I could shoot 9mm and save a few bucks during my range visits. At the time, buying a Beretta 92FS just was not in the cards so I needed a cheaper way to get a reliable 9mm. I figured the conversion barrel was the best solution, this way I don't have to learn a new trigger or anything, just continue practicing with the M&P but with 9mm in lieu of the .40S&W. So I purchased a Stormlake 9mm conversion barrel a little over 1.5 months ago along with 2-M&P9 Full size mags from GT Distributors ($25/ea+ S&H, not too shabby). I know why they were only $25 a piece for the mags though, you have to be PATIENT. I am going on two months and only got one of the two I ordered. Anyway, I digress. So, in the comfort of my home I field stripped the M&P40, set the .40S&W aside and slipped the 9mm conversion barell in it's place. Not a single problem at this point. The M&P40 and M&P9 use the same spring, so no need to change that just switch out the barrels. Put my .40S&W mags aside (I mean I buried them in my bag so I would not confuse the two because they look VERY similar). Put my 40 barrel into a soft glasses case and loaded my 9mm mag. Then I took it to the range and tossed in my laser boresighter (just in case). Everything was lined up fine, so I went ahead and removed the laser and slid the 9mm mag right into my M&P40. I put 100 rounds down the barrel with no issues. I have since purchased a few more 9mm mags (full price $40/ea [crying]) because I can't wait for that second mag from GTDist. and have not looked back since. The gun looks pretty sharp too in my opinion because its polished stainless whereas the stock .40 is black to match the gun. I still plan to keep the M&P40 chambered in .40S&W when at home or when CCW because I like .40 as a defensive round, but now I can keep shooting the M&P40 and save on ammo but shooting the 9mm.

So, in summation here are some numbers to ponder:
M&P40 New: +/- $510 (think they are a little more now)
Stormlake 9mm Conversion Barrel: +/- $160 (+ S&H) (expect about 1month for the barrel)
M&P9 Mags (GT Dist.): $25/ea (+ S&H) (expect 1 month each barrel not running concurrently, 2 mags=2months)

Total to have an M&P40 and a M&P9 in one gun: $720 (plus tax & S&H)
Or, cost of an M&P40 new and a M&P new (2 guns): $1020 (+tax)

So, for the money, I say it is worth it to be able to chamber .40 and 9mm in the same gun. I will still get a Beretta 92FS in the future, but for now, I like having the one gun be capable to shoot both size rounds. I would recommend the Stormlake Barrel to anyone interested. I hope someone out there finds this helpful! I know I would have, and I wouldn't have hesitated so long if I found something like this beforehand.

Happy Shooting!
 
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Great write up, makes me feel worse about buying my M&P 9c without first researching this and getting the .40 but you live and learn.
 
Yeah I have found it a huge help. I will carry 40, but for target shooting I would prefer the 9mm to at least save a few bucks. Honestly, I can switch out the barrels in no time at all. It just depends how long it takes you to field strip. I would recommend somehow separating the 40mags and the 9mm mags, I bought a small tackle box from wal-mart with a couple magazine sized components and I keep them all in one case. I will post a picture later tonight of my little macgyver contraption.
 
Botach Tactical was selling 10 round .45 M&P mags for $19.95, they might be worth checking out.
 
Hmm... will the top half of a M&P9 work on an M&P40 frame?

I honestly do not know. But I am pretty sure the springs and frames are identical. I think the only difference is the front of the 9mm slide where the muzzle breaches the slide during movement of the action is smaller because the outside diameter of the stock 9mm barrel is obviously a little smaller than the 40. So, you can't just drop a stock 9mm barrel into the 40 slide because it will move a little meaning your shots wont be accurate. Dont quote me on this specific item because I have not tried interchanging the parts between the 9 and 40. I do know that the 45 is a different beast all together and cannot be mixed with the 40 or 9 in any way
 
Great review, Dziner! Thanks for that.

Do you know if the conversion is also possible for the compact model of the M&P 40? I heard that it was, but not sure.
 
Reason being that I have full sized M&P9 and M&P40 pistols. The 9 is a non-MA trigger which is pretty solid and good for general use, but the 40 has had a Burwell job and is sweetness itself. Be nice to use that with cheaper ammo.
 
Reason being that I have full sized M&P9 and M&P40 pistols. The 9 is a non-MA trigger which is pretty solid and good for general use, but the 40 has had a Burwell job and is sweetness itself. Be nice to use that with cheaper ammo.

???

if you have one of each, why would you want to get a top half and / or conversion barrel?

edit: or you mean swap the slides and internals???

-sorry, a little confused.
 
I'm wondering whether I can swap the M&P40 top half and put the M&P9 top half on the gun so I can use the Burwell trigger on a 9mm.
 
Thanks for the review. Now I've got to take the leap and get the storm lake 9mm barrel for my xD .40
 
Great review, Dziner! Thanks for that.

Do you know if the conversion is also possible for the compact model of the M&P 40? I heard that it was, but not sure.

Yes the compacts are available now through stormlake. I actually looked at them the other day. Also if you want to get fancy you can get some of the barrels threaded or ported and they can be a 1/2" longer and protrude from the slide. If you like that look. My barrel did run around 160 but they are a quality company and not a "no name" so that is the only reason I spent a little more. I think you can find some other barrels for cheaper, but I just didn't trust the sites I saw them on so I opted to buy direct from stormlake and have been satisfied ever since.
 
I got a Storm Lake 357Sig barrel for my M&Pc.40. I got the 106mm (4.17") barrel because I noticed the 357Sig round loses like 50-80fps in a 3.5" barrel compared to a standard 4" barrel. So the barrel sticks out just a hair, but I get full 357Sig ballistics in a nice C/C package. It has been 100% so far and is VERY accurate.
 
Back from the death . Today I had the first chance to use my stormlake to shoot 9mm with my M&P40 and I'm very please with the result. 150 rounds down range with no FTF and no FTE it was just flawless. More range time now with chipper 9mm ammo.
 
Preface: This is a small "review" of the conversion barrel I bought for my M&P40. I am only writing this, because if I saw this before I ordered the barrel I would have made my decision a lot sooner.

I am the proud owner of an M&P 40 (yes PROUD, I love the gun). With the ammo supply issues not getting any better I decided to look into a conversion barrel so I could shoot 9mm and save a few bucks during my range visits. At the time, buying a Beretta 92FS just was not in the cards so I needed a cheaper way to get a reliable 9mm. I figured the conversion barrel was the best solution, this way I don't have to learn a new trigger or anything, just continue practicing with the M&P but with 9mm in lieu of the .40S&W. So I purchased a Stormlake 9mm conversion barrel a little over 1.5 months ago along with 2-M&P9 Full size mags from GT Distributors ($25/ea+ S&H, not too shabby). I know why they were only $25 a piece for the mags though, you have to be PATIENT. I am going on two months and only got one of the two I ordered. Anyway, I digress. So, in the comfort of my home I field stripped the M&P40, set the .40S&W aside and slipped the 9mm conversion barell in it's place. Not a single problem at this point. The M&P40 and M&P9 use the same spring, so no need to change that just switch out the barrels. Put my .40S&W mags aside (I mean I buried them in my bag so I would not confuse the two because they look VERY similar). Put my 40 barrel into a soft glasses case and loaded my 9mm mag. Then I took it to the range and tossed in my laser boresighter (just in case). Everything was lined up fine, so I went ahead and removed the laser and slid the 9mm mag right into my M&P40. I put 100 rounds down the barrel with no issues. I have since purchased a few more 9mm mags (full price $40/ea [crying]) because I can't wait for that second mag from GTDist. and have not looked back since. The gun looks pretty sharp too in my opinion because its polished stainless whereas the stock .40 is black to match the gun. I still plan to keep the M&P40 chambered in .40S&W when at home or when CCW because I like .40 as a defensive round, but now I can keep shooting the M&P40 and save on ammo but shooting the 9mm.

So, in summation here are some numbers to ponder:
M&P40 New: +/- $510 (think they are a little more now)
Stormlake 9mm Conversion Barrel: +/- $160 (+ S&H) (expect about 1month for the barrel)
M&P9 Mags (GT Dist.): $25/ea (+ S&H) (expect 1 month each barrel not running concurrently, 2 mags=2months)

Total to have an M&P40 and a M&P9 in one gun: $720 (plus tax & S&H)
Or, cost of an M&P40 new and a M&P new (2 guns): $1020 (+tax)

So, for the money, I say it is worth it to be able to chamber .40 and 9mm in the same gun. I will still get a Beretta 92FS in the future, but for now, I like having the one gun be capable to shoot both size rounds. I would recommend the Stormlake Barrel to anyone interested. I hope someone out there finds this helpful! I know I would have, and I wouldn't have hesitated so long if I found something like this beforehand.

Happy Shooting!

Have you had any extraction problems with 9mm barrel?
 
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