I was buying a used .40 cal Glock that came with a Lone Wolf conversion barrel that would allow the gun to shoot 9mm rounds.  As the guy behind the counter (it was a LGS, not Academy, etc...) was talking, he said re: the Lone Wolf barrel, "I wouldn't trust it for self defense..."

Honestly, I'm new to aftermarket barrels - never thought about 'em before, but this gun came with one.  As in all things, some people make great products, some make questionable products...but what little I have heard about Lone Wolf has been good, just speaking generally.

In some ways I can understand the thinking - you're taking a major component out, and replacing it with one not made by the gun's manufacturer.  OTOH, lots of outfits specialize in making items that are better than the original.

What are you're thoughts on this particular situation re: reliability of the .40 cal Glock w/ a 9mm LWD conversion barrel?

LWD is good to go

Perhaps the conversion aspect.

But they make them so they lock up tighter so it should be proved out with range time.

If you want reliability take the gun out and shoot it. Put 300-400 rounds thru it. No hang ups then it's good.
I have KKM barrels in two in 9mm & one in 45acp no hang ups over 500 rounds in each gun.

I would suggest that he was talking about reliability... using a straight .40 ejector and .40 extractor rather than those parts specifically designed for a 9mm, and not the quality of the Lone Wolf barrel itself... I have a G23 with a LW conversion that has a couple of thousand trouble free rounds through it... the .40SW barrel goes in when it comes home from the range...

It Depends...

There are a lot of brands and styles of aftermarket barrels.  

Caliber conversions can be spotty.  Cheap or specialty barrels can be fitted or not fitted in ways that cause problems.

They aren't wrong...it just depends.

I have personally had issues with a Lone Wolf conversion barrel.

I would agree with him.

I have had three aftermarket barrels between my 34 and 35, two KKM's and a Storm Lake. One took minor fitting and runs perfect, one needed a tight chamber reamed and the third I could not get to stop the FTFs. None had a noticeable difference in accuracy than the stock barrels. The KKM's are so smooth inside, I never have to brush the bore to clean them.

I never had any problem with my aftermarket barrels in my Glocks. I have a G23 with a 9mm LWD that is one of the favorite range guns in the family with tens of thousands of rounds having been fired through it. I vaguely remember that I also changed the extractor and trigger housing with ejector in it many years ago.

To not trust an aftermarket barrel is painting with a pretty broad brush.

Take it to the range a few times, and make your decision on reliability not conjecture.

I get the picture.  Thanks, everyone.

LWF is known for rough chambers. If yours is rough or tight use flitz on a cloth on a cleaning jag and a cordless drill.

But use the factory barrel for carry.

I have never had a malfunction with my 9mm conversion barrel in my Glock 22. This spans 115 grain Tula to 124 grain HST's.

Shoot your gun with carry ammo and other loads and see if it works. If it does work after an acceptable amount of time carry it.

Glocks are, like most modern designs, pretty much interchangeable, but that doesn't mean they are guaranteed a drop in fit. Unlike the AR15, and even it has issues if you assemble one from piles of parts.

It's a matter of the factory knowing that certain parts require they have dimensional compatibility. The +/- .015" has to be a good working relationship at the barrel cam, hood, slide, etc. If they are both on the tight side parts tend to hit instead of just clear, or gall instead of slide. Engineers work most of those kinks out but it's a continuing exercise as the parts are measured in production and then batch matched to the others as the stream into assembly. They choose which combinations to put into a gun, which makes the work well, and also saves them scrapping a whole bunch of stuff simply because it was all a tad too tight. Or loose.

We see this with AR building when an upper from one supplier and a lower from another are pinned together - or not - because the takedown holes either match coaxially and in size, with correct pin sizes, or you get the dreaded deadblow hammer out to make them fit the first 100 times. And the next gun? Loose as a Basic Training cycle gun with a lot of miles on it. Fortunately for the AR15 it's almost harmless, but for the lockup of barrel to slide in the frame, it can cause issues until all the parts can work together. You can't just drop in parts, and the factories don't either. The better ones are very consistent fits despite the parts not always working in some other gun as well.

It's even an issue with magazines - first recommendation for sciencing out FTF or FTE is change mags. The amount it presents to the slide and at what angle the ammo is pushed forward to hit the ramp is critical to feeding. In one study of mags that were designed for a combat weapon, a matter of .020" was all it took in mag width front to back - the looser ones rocked forward when chambering and it would cause FTF with ball ammo.

Promag anyone? Right - they have to fit and fit well, same as any other part of the gun. Again, the makers finesse this stuff before releasing it, the aftermarket will not have that proprietary information and cannot control the variations that exist in guns already being used and with higher round counts. So, you have to see how parts fit and if they will work.

No different with engines, valves, pistons, rings, and bearings have to be fitted. In some cases a matter of .005" could be catastrophic. Guns are a little bit more a clanky looser fitting machine but it doesn't mean it won't make a difference. Open the hollow point mouth a tad bigger on .45 ammo and have it snag the interrupted feed ramp on a 1911 and you get stoppages. Even ammo is an issue.

Shoot out the new parts same as a new gun to ensure correct working relationships, which also goes to taking it apart and inspecting the wear points to see if things are working together correctly. If you replace a part - you are the factory QC man for your one part assembly now.

I wouldn't trust ANYTHING until I had several hundred flawless rounds through it.

This for sure.....  Factory or aftermarket but I would probably carry it with the factory barrel if I were to carry it over the conversion barrel.

I don't trust Lone Wolf

I own a Lone Wolf barrel (converted my Glock .40 over to 9mm), and to some degree he has a point, but the problem does NOT lie with the barrel.

The problem lies with that many people rely on the .40 extractor and ejector, and while mine functioned most of the time with them - it wasn't ALL of the time like any original Glock should/did.

Change the right parts, test-fire the living shit out of it with the same ammo you will rely upon for self defense, and you'll know if you're good to go or not.  Mine is now good to go, and has been run by a two firearms instructors who wanted to see for themselves.

I have had two KKM barrels in .357Sig that ran without a hickup.  

I am ironing out two LW barrels right now.  They run fine on their own.  I have been having suppressor problems, which look to be solved by proper 147gr loads.

Just test it.

I see a lot of people run conversion barrels in USPSA and local pin matches without issue. Just test it.

In general, the aftermarket barrels have tighter chambers than Glock OEM barrels.  These tighter chambers MAY cause difficulty extracting spent brass.  

In addition, the 357 Sig or 40 S&W Glocks have a straight ejector while the 9mm ejector is bent slightly to the right.  The 357/40 ejector MAY cause erratic or weak ejection.  You can swap the trigger housing out for $8 if you need to.

My G22.3 shoots 9mm fine with the Alpha Wolf conversion barrel and stock (40) ejector.

Shoot it with the intended loads and see.

Had a handful of KKM and S3F barrels.  I have never had an issue with any of them and use them in defensive weapons with confidence.

You never asked this question re: Should I take advice regarding personal safety from a guy behind the counter at a gun shop? My answer would be, "No. You should rely on yourself for those answers."

Wring that gun to all hell in every imaginable scenario with the ammunition that you intend to use in it and make your own decision as to whether or not it works as needed. The ammunition to prove reliability is a zero dollar expenditure because the proof is overlaid with your training. If you are not training enough to prove the reliability of the firearm then I would question whether or not you are prepared to carry a firearm for defense. If I worked on the wording then maybe I could make it sound less rude but it wouldn't change the truth.

Train. Form your own opinions - do not rely on others for your opinions. Prove or disprove the reliability of the system yourself. Carry on. Don't sweat it when others doubt you - they don't know what you know.

This.

How much does LGS charge to make an "aftermarket barrel" OK for self defense use?

The extractor and ejectors are different between .40 S&W and 9mm Glocks, given the different dimensions of the cartridges. You need to consider why the engineers went this route. Personally, I would not trust a conversion setup for HD but would have no issues for range use.

I cannot figure out my Storm Lake barrel in my G21 Gen 4.  I have an occasional FTF every other mag with my Octane on it.  With my Osprey, I can run a hundred rounds and then it has a FTF.  Without a can, it seems hunky dory for a couple hundred rounds and then has a damn FTF.  And this is all with ball ammo.

Even LWD basically says don't trust their barrels with the literature they include with the conversion barrels.  It says that not all their conversion barrels work 100% in all the guns they are put into, and you should go out and shoot them to make sure yours works in your gun.  
The one I bought has been 100% through almost 1000 rounds now, and since I usually only test a gun to 300 rounds before I allow myself to carry it for defense, it has passed that limit and I would trust it.

I'm kind of a fan of factory barrels, they just seem to work for me.

300-400 flawless rounds thru said conversion barrel would make me trust it. I would swap out to the proper caliber's ejector and extractor as well. Say going from a .40cal to a 9mm in a Glock would warrant said ejector and extractor. Beta testing is your friend for sure! I vet every new pistol well before putting it in a holster and strapping it to a belt for a 10pm drugstore run for sure!

I would trust a name brand aftermarket barrel way more than a guy working at a gun shop

He's full of shit.  Mas Ayoob himself has BarSto barrels on several of his carry guns.  I sponsor him next week in Tucson and I'll ask again.

OP, are you gonna let that nerd tell you what to do?

Well, the OP did specifically mention that the employee was speaking about lone wolf barrels, so.....he's not wrong.

I've had one reliability issue with both the KKM barrel for the G26 and G17.

I blame myself on not shooting them enough.

Both times were with aluminum cased ammunition, too.

And LW conversion barrel at that, so he's even more not wrong.