.40S&W to 9mm Conversion Question

S

seeker_two

New member
I'm thinking about getting a used .40S&W (deals are pretty good right now) and a 9mm conversion barrel for cheap practice. I know that the 9mm might not be completely reliable, but it'll give me opportunity to practice failure drills in practice. I prefer the .40S&W for serious work in a full-size pistol.

I know the Glock would require a special barrel for conversion d/t the outer barrel diameter difference b/t the two calibers. I also know the M&P's use the same outer diameter, so factory barrels would swap easily. What about the SR40 or the PX4? Do they need special aftermarket barrels, or will factory barrels swap?

Thanks in advance!
 
I have a Glock 35 (40s&w) that I put a Lone Wolf 40-9 conversion barrel in. So far the gun has been reliable enough for range use. Maybe 2 FTE's out of almost 1000 rounds. I would bet that if i put a 9mm ejector in, then it would be 100%.
 
To my knowledge and experience, there is no easier & cheaper conversion from .40 S&W to 9mm than with the Glock 22/23.

Drop-in conversion barrels are ~$100. You can get a 9mm ejector that drops in easily and can still be used to run .40 cal ammo through. Most 9mm loads will cycle the .40 S&W recoil spring. Reliability of the 9mm recoil spring running .40 S&W is pretty much 100%.

From there, the 9mm mags you get for the 9mm glock can fit all other 9mm glocks you have so long as the frame is smaller than that of the mag. Ie 17 mags will fit the 17-26, 19 mags will fit the 19-26, etc. Same goes with the .40s.

Easy peasy.
 
I agree with noonesshowmonkey I own a Glock 22 and looked into either getting a new 9mm or getting a 9mm barrel for my glock 22 and I decided on the barrel for cost reasons and it works well for me.
 
Glock 22 and 27 both with conversion to 9mm. Both are utterly reliable. If something crazy were to happen I like having a couple carry pistols in multiple calibers.

So I think the AA Glock .22 conversion is next.
 
.40 cal CZ 75 is supposed to convert over to 9x19 and .357 sig fairly easily. If I'm not mistaken there are conversion kits being sold with all the parts you'd need. I only mention it because I've had an interest in the same conversions, and I prefer the CZ's over Glocks, personally.

I also believe that there are .22 cal conversions kits for the CZ as well, called the Kadet conversion kit, it seems a bit pricey, though.
 
.40 cal to 9mm conversion barrels

I have Lone Wolf 40 to 9 mm conversion barrels for both my G35 and G22. I have about 1000 rnds through the G35 and 500 through the G22.


Both barrels have been very good in accuracy & reliability. The guns functioned fine even with some locally produced lower power 9mm reloads. I have found the conversion barrels work with both 9 mm and .40 cal magazines.


I think having a conversion barrel is useful for training, to give you flexibility if/when we go through another period of limited ammunition availability, and to give you the opportunity to take advantage of those happy times when you find a good sale.


I have a Storm Lake conversion barrel for my S&W M&P and a BarSto conversion barrel for my Sig 226 DAK. I have had good experiences with those barrels too but in truth I haven't shot either one all that much. 300+ round each probably? Shooting both guns more frequently in both 9mm and .40 cal is going to be one of my winter projects. (The Sig DAK was an issue duty gun for about 9 years -- we now issue various models of Gen 4 .40 cal Glocks. I now carry a G22)

If I was considering using the 9mm barrel as primary for defensive use I'd function test it first with a bunch of the service ammunition you planned to use.
 
the m&p is the cheapest/easiest to convert.
66 dollars for a new factory 9mm barrel drops into the 40 cal slide and functions fine.

the next would be the glock with the conversion barrel.

CZ would be the most expensive/complex as it requires a slide change as well as barrel to work.

9mm mags function for both 40 and 9mm, so I generally only pick up the 9mm mags when I get new/spares.
40 cal mags for the cz won't let you load 9mm. sadly found that out at the range having only brought 40 cal mags. feed lips are too wide to hold the rounds in.
 
the m&p is the cheapest/easiest to convert.
66 dollars for a new factory 9mm barrel drops into the 40 cal slide and functions fine.
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Even the factory recommends AGAINST this. Use a conversion barrel with proper breech dimensions. It's often reported that people do this... however, you shouldn't do it. And you shouldn't expect very good accuracy if you do.
 
few hundred posts that say it works and works pretty well.
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You're not supposed to do it and that's it.

If SW says no, that means NO. You think SW does not want to sell barrels and make money? Like every business, they are in it to make money, and selling conversion barrels is popular. So why does SW say don't to do this? It's because they know something you don't. I would not second guess them.
 
I've got Lone Wolf 9mm conversion barrels for my Glock 27 and 23. I use them for range / training for people that are somewhat recoil adverse.

I got 9mm mags to use for both and have never had any problems with the G23.

The G27 had occasional FTEs. I replaced the steel custom recoil rod and springs with the stock recoil spring assembly - has worked like a champ ever since.

YMMV.

Since my wife has moved up to being interested in shooting more - I was able to justify buying a G19 for the house. ;)
 
By the time you get a conversion barrel, magazines, recoil spring, extractor, etc., maybe it would be more cost effective and time efficient to buy two used pistols.
 
somerled said:
By the time you get a conversion barrel, magazines, recoil spring, extractor, etc., maybe it would be more cost effective and time efficient to buy two used pistols.
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With the Glock 22 or 35, all you need is the conversion barrel, which is a lot cheaper than buying a used 22 or 35.

The mags will work with 9mm rounds.

(Been there, done that.)

I found, however, that the Lone Wolf barrel liked hotter loads when shooting 9mm.
 
By the time you get a conversion barrel, magazines, recoil spring, extractor, etc., maybe it would be more cost effective and time efficient to buy two used pistols.
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There is something to this.

I had a number of SIG's in 357SIG, and bought a spare .40 barrel for each (factory barrels in those cases, drop right in either caliber, 9mm doesnt, and required an aftermarket barrel), along with a case of ammo for each.

Other than confirming function, those .40 barrels sat on top of those cases of ammo, and were never used. A good bit of money tied up, and still only one gun for each set.


I also bought a Lone Wolf 40-9 conversion barrel for my Glock 31 (357SIG). I ended up shooting more 9mm out of that gun than 357SIG, as the 31 was beating itself to death using 357SIG ammo. I simply dropped the LW barrel in and used 17 mags, with no other changes, and never once had an issue with function or reliability.

The biggest thing that Lone Wolf barrel did for me was, convince me, I was wasting my time with the 357SIG, and I went back to 9mm for pretty much everything. No need to bother with any more conversions. :)


Ive had a number of "convertibles" over the years, handguns and long guns, and in pretty much all cases, once I settled on a combination I liked, everything else just sat in a box on the shelf. I think more often than not, that extra money would be better spent on another "complete" gun.

In this case though, if you can pick up the gun you choose cheap, and it works well with just the barrel/mag swap, hey, have at it. Dont be to surprised if you dont ever change it back though, so I wouldnt get to carried away buying a lot of extra ammo or accessories, for the barrel left in the box.
 
Not converted ANYMORE

I used to want to have a cool gun I could swap barrels on but I have gone over to AK's camp on this. Shoot what the gun is designed for. Save a while longer and buy the other gun. If one of them gets dusty from neglect or you don't like it, sell or trade it.

Pico
 
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