Glock Replacement Barrels

By John Farnam

Glock Replacement Barrels
Glock Replacement Barrels
Defense Training International, Inc
Defense Training International, Inc

Ft Collins, CO –-( Many comments and questions about Glock “modifications” after my last Quip, “Three Fighting Rifles That Make My Recommended Best List“.

With regard to GLOCK replacement barrels ( ) , there are Four reasons why they are currently popular, at least in some quarters:

(1) Hobby Reloaders: Most aftermarket barrels claim to have “fully-supported chambers.” In plain English, this means the feed-ramp is extremely steep, which means the pistol will not feed as reliably as it does with the factory barrel, but the case will not extrude as much into the feed-ramp recess upon firing, an aid to reloaders.

Glocks are designed to reliably shoot factory ammo (new cases). Accordingly, fired cases often come out with a slight bulge near the base. “Fully-supported” chambers in aftermarket barrels are thus designed solely to attract reloaders.

As noted, Glock replacement barrels invariably make the pistol less reliable, and are therefore not recommended.

(2) Glock Replacement Barrels & Tight Chambers: Many, probably most, aftermarket Glock barrels “feature” tight chambers. This is to appeal to those for whom accuracy is the sole goal.

Unfortunately, tight chambers and reliable feeding are not compatible. Tight-chambered pistols may be suitable to some forms of banal recreation, but are obviously not recommended for any species of serious fighting purpose.

In fact, tightly-fitted guns, in general, are NOT recommended for serious fighting  purposes!

(3) Glock Replacement Barrels & Cut Rifling: Aftermarket barrels are “cut-rifled,” with traditional lands and grooves. Polygonal rifleing, found on factory Glock barrels, requires sophisticated industrial processes, out of reach for most small accessory manufacturers.

Unjacketed (lead) ammunition is not recommended for use in polygonal barrels, as it makes a gummy mess that is difficult to clean. Cut-rifled barrels, when used with unjacketed ammunition, will also generate a gummy mess, but it is a little easier to clean up!

Glock Replacement Barrels
Glock Replacement Barrels

(4) Glock Replacement Barrels & Caliber Conversion: The current trend among police departments and federal agencies is in the direction of 9mm. This means that there are many perfectly serviceable police trade-ins available, in 40S&W and 357SIG calibers, that can be purchased at attractive prices.

With the addition of a conversion barrel, many of these pistols can be easily changed-over to 9mm.

The result is usually a pistol of only marginal reliability, but it may suffice for non-serious purposes, at least for some.

As you’ve probably concluded, I don’t recommend any replacement Glock barrel, for reasons enumerated above. My recommendation, with very few exceptions, is to leave your Glock pistol stock, just the way it comes out of the box.

I recommend never shooting unjacketed (lead) ammunition in any serious pistol. I seldom see stock Glocks fail. I see “screwed-with” Glocks do little else!

LaserLyte FSL-4 laser on Glock G19 Pistol
LaserLyte FSL-4 laser on Glock G19 Pistol


About John Farnam & Defense Training International, Inc
As a defensive weapons and tactics instructor John Farnam will urge you, based on your own beliefs, to make up your mind in advance as to what you would do when faced with an imminent and unlawful lethal threat. You should, of course, also decide what preparations you should make in advance, if any. Defense Training International wants to make sure that their students fully understand the physical, legal, psychological, and societal consequences of their actions or inactions.

It is our duty to make you aware of certain unpleasant physical realities intrinsic to the Planet Earth. Mr Farnam is happy to be your counselor and advisor. Visit:

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Scott G Smith

Thank you for your great info, I was ready to go through my Glock 19 from barrel to trigger, now I will stick with my factory barrel, this should be required reading for all glock owners.