LoneWolf Glock 27 40 Caliber to 9mm Conversion


Recently you may have read my blog related to the Glock 27 that I purchased on Gunbroker.  This has become my EDC CCW when not wearing a suit, tuxedo or needing a deep concealment or the pocket concealment option. My Sig P938 is perfect for those dressier and deep concealment occasions.

Since I did not have the Glock 27 in 40 caliber prior to the mass ammunition shortage of 2013 like many looking to buy ammo no I was left with no real opprotunity to shoot this gun. As mentioned in my previous article Action Sports did let me buy rounds to shoot at their range but since I prefer to shoot at Oakland County Sportsman’s Club I was high and dry.

Lone Wolf makes a a series of Glock barrels that can be used for shooting reloads, adding a ported barrel, adding a threaded barrel or converting your G27 to a 9mm or 357 SIG. Sine I have an abundance of 9mm that I bought pre ammunition apocalypse I purchased the  $109 Lone Wolf barrel. It comes in different lengths for all the various Glock 40 caliber models from the full size down to the subcompact G27. The barrel is made from 416R stainless steel and boasts  tighter dimensions then the standard Glock barrels.

It is not required but highly recommended that when using the conversion barrel that you change the magazine to the appropriate caliber. Many shooters also suggest changing the slide spring as well. If I was to carry my G27 everyday as a G26 then I certainly would change the spring however for my purpose of getting practice when 40 caliber ammo is in a shortage it worked just fine.


  • My Glock 27 was a well broken in used model
  • I did not replace the slide spring
  • Magazines used included 19, 26 and 27 models
  • Ammo was cheap Tul ammo FMJ 115 grain 9mm


the installation of the barrel is as easy as cleaning the Glock. Take the slide off remove the spring and old barrel. Then put it back together using the new Lone Wolf barrel. It is easy peasy. If you are swapping for a lighter spring you would also swap that out at this time.


The gun performed much as I expected it went bang when I pulled the trigger ALMOST every time. This is an important note regarding the ALMOST. If you plan to carry a gun for self defense then I do not recommend this barrel change. I had 2 failures to feed when shooting 250 bullets down range. When firing the gun in a life and death situation failure to feed or eject is not an option.

However as noted above I did not change the slide spring and the spring I have on this G27 is very heavy. I have noticed the gun does not always lock open on the last shot when firing 9mm due to it not cycling all the way back. Changing the spring is likely to fix this but I am not risking my family’s safety when I could just buy a G26. I also want to note one of those failures was when using a G27 magazine which is not recommended at all.

Those 2 FTF aside I was pleased that I had no FTE’s and accuracy was not affected by the change at all. The first series of Lone Wolf Barrels had issues related to extraction from what I have read. A change has been made that reduces this to a reported 1% issue. Light ammunition is often the cause of the issue and they recomend firing a heavier duty 124 grain ammunition. The alternative is the following:

1    Clean and lube your slide and barrel.
2    Shoot 1 mag to 1 box of good quality +P or +P+ ammunition through the barrel.
3    Try the FTF ammunition again. If it runs… great!  If you experience more failures you will have a couple choices to make:
Fix A        Reduce the recoil spring weight to 11 lbs. Cost is about $25 for stainless steel guide rod and reduced power spring.
Fix B        Shoot 124 gr or a better quality 115 gr ammunition exclusively. The FTF 115 gr ammunition you are currently using is no longer a valid option.


In short the Lone Wolf barrel was inexpensive, held up well, was easy to install and allowed me to get some practice when 40 caliber ammunition was at a shortage. If you are going to the range and want to cut the cost of shooting 40 caliber then this is a highly recommended conversion. I love carrying a 40 caliber gun for self defense and this barrel exchange allows me to do that without breaking the bank on practice ammo.

If you have a G27 or another model Glock based 40 caliber and are interested in shooting either 9mm or 357 Sig then I highly suggest this conversion kit. If you have one please leave your notes and comments as we love to hear from others that have tried these products as well.

Charles is the editor for 248 Shooter a midwest based gun news and gear review site as well as Online Content Director for On Target Magazine. He is an avid student taking classes from top tier trainers around the country. Charles shares his love for training as well as experience and opinions on some of the most talked about gear and products used by competitive shooters, military, leo and civilians.