Conversion Barrel's

[hundy]

I have heard people in the past at firearm events talk about conversion barrels. Today I had seen a add for one. I have several M&P's in both 40 and 9. I had seen a add for a Conversion barrel for a 40 making it a 9.

I never really looked into it. Is it that simple? Change out the barrel, and magazine? So the upper receiver will load and eject the round?

Can you convert a 9 to a 40? Or just a 40 to a 9?

I would never really even consider doing this, however, I have one of each M&P except the 9c. So if all I need to do is get a conversion barrel for my 40c, I guess it would be like having both.

Sorry for my ignorance on the subject.

Thank you

Jay

[seal20]

Yes, it's that easy to go from 40 to 9 on a M&P. You can't go 9 to 40 due to the difference in the breach face.

[hundy]

Thank you

Thank you. Good to know. I guess I can have a 9c now.
Honestly learn something new everyday.

Thank you

Jay

[saudadeii]

There are quite a few people using OEM barrels successfully. Midway just got (and sold out quickly) S&W 9C barrels. I was able to get one for $71 shipped.

[Monkeywrench]

I've got the 40c with and a Storm Lake conversion barrel. Technically you would need a recoil spring/guide rod assy. also. I only use my conversion at the range and leave my 40 recoil/rod in and haven't had a problem. I wouldn't recommend it for a self defense gun though.

[003]

You will also have to get the correct magazines. Keep in mind that the 9mm is .355 while the .40 is a true 40.

[rsrocket1]

I don't have a 40c/9c, but the 40 FS and 9 FS pistols use the same recoil spring. I do admit that I use separate recoil springs when swapping between calibers. When shooting 9mm in my M&P 40, I use my original M&P 40 recoils spring that has about 20,000 cycles. The spring is a bit softer than a new one and aids in ejecting the 9mm cases a bit further.

I bought a factory 9mm barrel when the Storm Lake conversion barrels had dried up on the market. It works perfectly with 9mm magazines and I have to admit that I am more consistently accurate with this setup than I am with the original 40 setup.

[Monkeywrench]

I don't have a 40c/9c, but the 40 FS and 9 FS pistols use the same recoil spring. I do admit that I use separate recoil springs when swapping between calibers. When shooting 9mm in my M&P 40, I use my original M&P 40 recoils spring that has about 20,000 cycles. The spring is a bit softer than a new one and aids in ejecting the 9mm cases a bit further.

I bought a factory 9mm barrel when the Storm Lake conversion barrels had dried up on the market. It works perfectly with 9mm magazines and I have to admit that I am more consistently accurate with this setup than I am with the original 40 setup.

Interesting. I have two complete uppers for my FS and the 40 uses a spring with green paint while the 9 has blue paint. I can't feel much difference between the two though.

edit: Just looked it up and the compacts share the same part numbers so you don't need a guide rod/spring for the conversion. Looks like the FS used to use the blue spring for 9/40 but they recently started using the green for the 40. The blue is 15lbs. and the green is 17lbs.

[Beendare]

Do these conversion barrels just drop in?

I have a Glock 23 [older generation] and wouldn't mind a 9mm barrel for my wife [and me]...but I don't need a match barrel.

I was on the KKM site and they list conv barrels being slightly oversize for gunsmith fitting....

[jdmacl]

I have multiple .40s from various manufacturers, including a M&Pc.

I've never considered stepping down to a 9mm with them, but I own .357 Sig barrels for all of them.

It's a very simple, drop-in, caliber change with no change needed of magazines, recoil springs, etc.

Have you ever tried a .357 Sig? It's a very fun round!

[BennyW]

You will also have to get the correct magazines. Keep in mind that the 9mm is .355 while the .40 is a true 40.

Being a skin flint, I held off on buying 9mm mags to go with the (cheaper non-conversion) S&W 9mm barrel for my M&P 40 (full size). Factory range ammo such as WWB & UMC functioned perfectly, but I discovered that my buddy did something to the cases on his reloads and the diameter was just small enough to create a double feeding jam-o-matic unless 9mm mags were used. YMMV

Another fun fact - the 40 follower locks back with either one or two 9mm rounds still in the mag. I forget which, it has been a few years. This minor inconvenience paled in comparison to the thrill of stuffing 14 rounds into a perfectly legal magazine.

As far as Glocks and Sigs go, I have never experienced a malfunction when using conversion barrels and their corresponding mags. Again, YMMV.

[S.P.F.]

I have a 9mm conversion barrel for my .40 Glock 27, and a .40 conversion barrel for my 10mm Glock 20. (both Lone Wolf brand). Totally drop-in.

Both will "work" with just a mag change and the G27, and no other changes on the G20. But the G27 ejects a bit weakly, and with some BTF's. I use a 2 lb lighter recoil spring, and it helps. Some say, you should also change extractors, because of slight geometry differences there, but since my purpose is sporting, I don't.

I doubt, that even if I were to make all the "small" changes in a conversion setup, that i'd still not trust it for hunting carry or defense. Just for fun, and the lesser cost of ammunition in each case.

[SB1964]

Do these conversion barrels just drop in?

I have a Glock 23 [older generation] and wouldn't mind a 9mm barrel for my wife [and me]...but I don't need a match barrel.

I was on the KKM site and they list conv barrels being slightly oversize for gunsmith fitting....

Had a G23 for a few years & didn't really like it. I put a Stormlake black ss 9mm barrel on it & it's impressive. More chamber support & a lot more accurate, now ammo's a bit cheaper too. I went back & forth with the ejector housing & decided to keep the stock one in place, it works just fine. Reliable at about 600 rounds so far, just an occasional pop fly.

Guys on here swear by the KKM also. Most vendors suggest "oversize" & potential issues. Mine locks up nice, I love it & use 9mm mags.

[Hoser!!]

I have a G23 with a Lonewolf conversion barrel. Works just fine using my stock magazine. I bought a G19 magazine just in case. Not sure why but to me, 9mm is not accurate after 15 yards. Maybe it's the cheap Ammo I use. Lol