View Full Version : Conversion Barrels: Legit or Hack
PrivateCitizen
05-06-11, 01:28
As I approach the next acquisition, a new M&P compact, I recall many a thread about conversion barrels. "Just get a 40 and drop a 9 barrel in it"
I've never personally had one or even shot a pistol equipped with one so I am ignorant on the matter.
Are conversion barrels 'reliable' or is the realization of the promise just more trouble than it is worth?
I am considering an M&P40c rather than a 9c just to have the plurality. I shoot 9mm more-or-less exclusively but if all is equal I don't mind the extra for the barrel/mags.
This IS NOT a bigger caliber question. Local SO uses .40SW and I may have the op to shoot with them with dept supplied ammo.
If conversion barrels can run, great. If it is gonna foul up (FTE, FTF, etc) it isn't worth the bother.
Would appreciate related experiences.
legit for practice, don't consider it for carry/duty.
Alaskapopo
05-06-11, 01:55
I have used 9mm conversion barrels for .40 sw sigs and Glocks. Worked well but as the previous poster said use them for cheaper practice not for carry.
Pat
i just got a KKM conversion barrel for my glock yesterday. so far it's worked flawlessly. 200 rounds, no problems at all. I havent tested it enough to carry it yet, but i bought it for cheaper range fees.
legit for practice, don't consider it for carry/duty.
I have seen people talk about the barrels but for my money and my life I agree with the above.
The 9mm slide is different from the 40/357.
I've had a Lone Wolf 9mm conversion barrel for my Glock 35 (40S&W) for several years. I've fired at least 1000 rounds thru it with no FTFs or FTEs. However, I did get a lower weight recoil spring (13#) for it because ejection was weak with the standard 17#. :)WB
I bought a 9mm storm lake conversion for my .40 xdm. I haven't had any failures but it doesn't seem as accurate in 9mm as it is in .40.
I end up not using it much since I have lots of 9's and only one .40.
Probably not the smartest money I've ever spent, $160 for the barrel and 4 mags for around $80. I'll never get $250 of use out of it. If I didn't have other nines maybe it would be different.
legit for practice, don't consider it for carry/duty.
You often hear this said: "Don't use a caliber-conversion barrel for carry."
I assume this is because it is thought that the conversion barrel can affect reliability. But I haven't tried enough conversion barrels to observe any issues firsthand.
How exactly DO caliber-conversion barrels compromise reliability? Also, is there some strong evidence out there that conversion barrels simply can't be reliable, on ANY pistol platform, regardless how well made the barrels are?
Not debating with you Sky, just gathering info on this area because I've considered the OP's scenario myself (buying a .40, for ammo commonality and just to try another caliber, but getting a 9 conversion barrel so I can practice with the ammo that I have a lot of).
Don Robison
05-07-11, 14:09
My primary training pistol is a G22 with a Lone Wolf 9mm conversion barrel. I've got a little over 10K of various ammunition through the barrel with no issues.
Would I carry it? In a pinch; I would just because I know it's reliable and it's handled SD ammo no different than FMJ training ammo.
You often hear this said: "Don't use a caliber-conversion barrel for carry."
I assume this is because it is thought that the conversion barrel can affect reliability. But I haven't tried enough conversion barrels to observe any issues firsthand.
How exactly DO caliber-conversion barrels compromise reliability? Also, is there some strong evidence out there that conversion barrels simply can't be reliable, on ANY pistol platform, regardless how well made the barrels are?
Not debating with you Sky, just gathering info on this area because I've considered the OP's scenario myself (buying a .40, for ammo commonality and just to try another caliber, but getting a 9 conversion barrel so I can practice with the ammo that I have a lot of).
Changing the barrel doesn't change your breech face dimensions, location and engagement area of the extractor, location or length of the ejector, the slides weights can be a little different, etc.
Don't you think that Glock would make 1 fullsize slide, then just make different barrels that work for all of them if they could?
They've used the same springs in guns to cut down on parts inventory...you don't think they'd do the same with CNC machined slides?!
Every shooter I've seen try to use a conversion barrel in a class has had their gun puke on them. I would never recommend using one for anything other than practice/recreational use.
Changing the barrel doesn't change your breech face dimensions, location and engagement area of the extractor, location or length of the ejector, the slides weights can be a little different, etc.
Don't you think that Glock would make 1 fullsize slide, then just make different barrels that work for all of them if they could?
They've used the same springs in guns to cut down on parts inventory...you don't think they'd do the same with CNC machined slides?!
Every shooter I've seen try to use a conversion barrel in a class has had their gun puke on them. I would never recommend using one for anything other than practice/recreational use.
yep, that's basically what i was gonna say.
a defensive pistol should be optimized for the round it fires. tossing in a caliber conversion barrel, even with the correct extractor, ejector and mag doesn't give you the exact geometry of the 9mm gun.
I mean the whole reason people buy 40 instead of 9 is the extra power in a defensive scenario-so may as well use it. it can be a great tool for training though, a couple extra malfunction clearances will keep you sharp, and 9mm is always cheaper.
Legit if you are going from .40 S&W to 357 SIG or vice versa... :D
-Tom
Heartbreaker
05-08-11, 01:19
There's no reason not to carry with a conversion barrel, assuming you have shot it enough to determine it cycles 100%, just as you would changing ammo or anything else. I've found KKM conversion barrels to be more accurate and have better chamber support than stock Glock barrels (though you miss out on the polygonal rifling). Going from 10mm to .40 on my G20 is nice, same mags, same rim so the extractor doesn't know the difference, and the heavy slide/spring handles .40 like it's hardly there.
Carniemedic
05-08-11, 07:42
I bought a Storm Lake 9mm conversion barrel and it fit in my Gen 4 Glock 23 well. It just dropped right in locking up tight that was the good part. The bad part was that I had 1 FTE within the first 100 rounds, and the trajectory of the ejected rounds was changed so much that they were hitting me in the forehead about 1 out of every 5. The accuracy was not very good either. I’m not saying that I’m a match level shooter, but I had much more tighter groups with the .40 caliber factory Glock barrel than the Storm lake 9mm conversion barrel. I ended up selling the barrel and the 9mm mags then saved up some more dough and I bought a Glock 17.
...."Just get a 40 and drop a 9 barrel in it"
In general:
40 to 9 usually works.
45 to 40 sometimes works easily sometimes not.
45 to 9 is usually a lot of trouble.
The converted set-ups that will run require more detailed cleaning when in order to switch back and forth.
Its after the spent shell is extracted that you find out whether the pistol will run or not. Once the shell is mostly clear of the chamber, it will begin to be pushed toward the ejector side of the breech. If the extractor travel is limited enough that it won't remain in contact with the rim, you can expect to have problems.
Assuming the slide cuts allow the extractor adequate movement to work both calibers, you would want to clean the extractor and its slot when you switch. Fouling built up under the extractor will limit its travel and cause trouble. Since the extractor moves a certain amount for 40, the gap between the extractor can fill up with fouling and not impede its operation - in 40. When the extractor has to reach further over to stay on the 9mm it may or may not do it.
For a pistol with an easily removed extractor, like the Glock or the 1911, this is easy to stay on top of. The M&P extractor isn't set up to be easily removed.
Will it work? Probably - for a while. I don't think the M&P is well suited for the idea though. By the time you've shot enough to make the idea worthwhile, it will probably begin to act erratically.
Also, care to gamble on whether the 9mm barrel will shoot to a similar point of aim as the 40? This is easy to deal with if you have repeatable, adjustable sights. I wouldn't want the annoyance of dealing with a new point of impact and "fixed" sights
If you're going the M&P route you may be better off buying two guns.
I have both a 40 and 9 conversion for my FS M&P 357. About 1k thru each, no issues. Definitely a drop in accuracy going from the 357 to the 40 but thats the round not the barrel IMO. They both fit well, no slop, etc.
In general:
40 to 9 usually works.
45 to 40 sometimes works easily sometimes not.
45 to 9 is usually a lot of trouble.
The converted set-ups that will run require more detailed cleaning when in order to switch back and forth.
Its after the spent shell is extracted that you find out whether the pistol will run or not. Once the shell is mostly clear of the chamber, it will begin to be pushed toward the ejector side of the breech. If the extractor travel is limited enough that it won't remain in contact with the rim, you can expect to have problems.
Assuming the slide cuts allow the extractor adequate movement to work both calibers, you would want to clean the extractor and its slot when you switch. Fouling built up under the extractor will limit its travel and cause trouble. Since the extractor moves a certain amount for 40, the gap between the extractor can fill up with fouling and not impede its operation - in 40. When the extractor has to reach further over to stay on the 9mm it may or may not do it.
For a pistol with an easily removed extractor, like the Glock or the 1911, this is easy to stay on top of. The M&P extractor isn't set up to be easily removed.
Will it work? Probably - for a while. I don't think the M&P is well suited for the idea though. By the time you've shot enough to make the idea worthwhile, it will probably begin to act erratically.
Also, care to gamble on whether the 9mm barrel will shoot to a similar point of aim as the 40? This is easy to deal with if you have repeatable, adjustable sights. I wouldn't want the annoyance of dealing with a new point of impact and "fixed" sights
If you're going the M&P route you may be better off buying two guns.
Another option is to simply buy a complete slide assembly from S&W in the new caliber. The frames of the FS guns are identical. If one simply purchased a complete slide assembly including the barrel, RSA and sights then presto, new caliber. Corresponding mags also. The issues re. reliability of the conversion barrel would be eliminated. S&W has those for $226.32 in stock. I just made my M&P fs 40 into a 9mm by doing just that.
I have a Full size M&P .40 that I added a 9mm S&W barrel (and two 17 rd 9mm mags) to last August. I have had zero problems with either caliber, and the cheaper 9mm ammo has been a plus for range and classes.
I liked it so much that I am picking up a .40 Shield tomorrow (state of Maryland's 7 day wait grew to 2 weeks because of the panic buying), and I already have a 9mm barrel and an 8 rd ext 9mm mag for it. I am still using .40 cal. self-defense loads and the occasional 100 round target box from Walmart, but the 9mm setup has worked so well, I would trust it -- after running a box or two of self-defense 9mm loads to make sure that there are no problems.
S&W has those for $226.32 in stock. I just made my M&P fs 40 into a 9mm by doing just that.
If you could post a link or PM the link, I'd appreciate it. You just saved me from buying an M&P FS 9mm.
-Jenrick
Another option is to simply buy a complete slide assembly from S&W in the new caliber. The frames of the FS guns are identical. If one simply purchased a complete slide assembly including the barrel, RSA and sights then presto, new caliber.
The ejector is in the frame. Are you sure the 9mm and .40 ejectors are placed in the same position, and are the same shape and length?
The ejectors have the same part numbers for all three calibers (.357 Sig,, 9mm, & .40). the recoil springs are also the same. The slide has a slightly different shape at the barrel hood end (.40 & .357 are the same -- 9mm is different).
crazymoose
01-11-13, 23:32
I have never had issues with conversion barrels, but I read a range of differing experiences other people have had. It could be a couple of things:
-Tolerance stacking issue. You're talking about an oversized breach face, and an extractor that's not ideally placed for a smaller round. In addition to small manufacturing variances, you also have to factor in some variances in rim dimensions on different brands of 9mm rounds.
-Limp wristing (at least with Glocks). You've got a pistol whose slide is weighted (and in Gen 4, sprung more heavily, I believe) to handle a round with more energy. The gun will be more susceptible to malfunction from improper gripping.
If you could post a link or PM the link, I'd appreciate it. You just saved me from buying an M&P FS 9mm.
-Jenrick
There is no link. Its a simple call to S&W customer service. 800-331-0852. They will ask if you want it with night sights or without.
The ejector is in the frame. Are you sure the 9mm and .40 ejectors are placed in the same position, and are the same shape and length?
Yes im sure. Only the slides themselves and barrels are different. Mags also of course. The ejectors and extractors are the same and in the same position. I believe the firing pin is also the same, though it doesnt matter since the slide assembly comes with one any way. This is the better option because you eliminate the reliability issue that could come up with a conversion barrel that doesnt take into account the weight variances of the different slide. If the additional caliber is only to be used for range play then i guess a conversion barrel alone works. What i have noticed is that the prices of a good conversion barrel vs just getting a complete slide assembly from S&W is negligible (for me). Particularly since the extra set-up then works for defense. When people like LAV tell us that conversion barrels should be used for training but not for carry, thats a clue.
Muchas gracias. Going to order one Monday.
-Jenrick
There's no reason not to carry with a conversion barrel, assuming you have shot it enough to determine it cycles 100%, just as you would changing ammo or anything else. I've found KKM conversion barrels to be more accurate and have better chamber support than stock Glock barrels (though you miss out on the polygonal rifling). Going from 10mm to .40 on my G20 is nice, same mags, same rim so the extractor doesn't know the difference, and the heavy slide/spring handles .40 like it's hardly there.
I have put more rounds downrange in my two conversions (Shield 40 into 9 and 40C into 9) in their non-native calibers than in their native ones. We are talking about thousands of rounds, including hundreds of HP rounds.
Of course I am going to trust these as much as I trust any gun that has been well tested by me. While nothing is 100%, I trust these guns and regularly carry them in 9mm.
But that is just me; YMMV.
I got the slide assembly from S&W and no barrel or RSA. The guy who took my order was mistaken re. what would be contained with my order. What's worse is that barrels are out of stock. S&W is paying for shipping the slide back to Springfield though. Apologies.
Btw I now have an un-opened 9mm 10 rd mag I don't need.
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