I Want to buy a barrel (lonewolf I believe) that is m and fits in a 33 but, a gun shop way back when, said I would need other parts too, What else would I need to safely shoot 9mm. Thanks!

Watch this video. The guy was having some problems failure to eject and failure to feed.

Watch "Lone Wolf Dist 9mm bbl in Glock 33" on YouTube


Take a look at lonewolf's page on some specifics. Hope this helps a little bit.

Lone Wolf Distributors - Products - Conversion
https://www.lonewolfdist.com/Products.aspx?CAT=241

I converted my glock 22 to 9mm with the lw barrel.  A third of my 40 magazines will work with 9mm, the rest will occasionally not feed.  Sometimes brass will hit me in the forehead so I changed my extractorwhichdidnt solve the problem.  Might be I need a weaker recoil spring.

Shoots accurate though a couple more inches high.

I don't know much about glocks, but it seems to me that if you change to a different diameter rim, you would need to change the slide.

I don't know much about glocks, but it seems to me that if you change to a different diameter rim, you would need to change the slide.

Not necessarily.  Going down in caliber means just the bore size changes.  The barrel's outside diameter can stay the same and still fit the slide.

I've seen people post videos that show FTF and other failures mostly caused by 115gr 9mm rounds in a converted Glock.  Heavier rounds tend to work more reliably.

To compensate for the weaker rounds, you can change out the guide rod and recoil spring. 

After all the parts, problems, and wasted ammo trying find the right combination, you're probably better off just buying a 9MM Glock. 

 

Since the breechface and extractor are fitted to a certain diameter rim, a cartridge with a different size of rim just won't fit quite right.
A new slide with the correct breechface and extractor should work. Then you need the correct magazines because the feed lips have to be different.
Then comes the barrel. I think it's cost effective to just buy a 9mm pistol.

Since the breechface and extractor are fitted to a certain diameter rim, a cartridge with a different size of rim just won't fit quite right.
A new slide with the correct breechface and extractor should work. Then you need the correct magazines because the feed lips have to be different.
Then comes the barrel. I think it's cost effective to just buy a 9mm pistol.

http://www.thehighroad.org/archive/index.php/t-510616.html

According to the people in that thread (who sound like they actually have done it), the extractor works fine for other size cartridges.

http://www.thehighroad.org/archive/index.php/t-510616.html

According to the people in that thread (who sound like they actually have done it), the extractor works fine for other size cartridges.

...
To clarify:
I was describing the general design of a breechface, and a typical caliber conversion. ..not specifically glocks.

with the failure to feeds the companys usually recommend changing out springs. I ordered a 9mm guide rod spring for my 4th gen. Havent used it yet cause i ended up buying a 17 anyways. But might wanna look into that.