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  • Double Diamond 9mm Premium Conversion Barrels for Glock Gen1-4

Double Diamond 9mm Premium Conversion Barrels for Glock Gen1-4

$179.99 to $289.95
SKU: 1012

Easily convert your Glock 22/23/31/32 to fire 9mm with just a simple drop-in barrel swap!

Double Diamond Premium Barrels are manufactured in the USA and are designed to deliver better accuracy reliability, and so much more.

Twist rate for the Rifling in all Double Diamond barrels:

9mm - 1/10" Right Hand

10mm/.40 - 1/16" Right Hand

.45 ACP - 1/16" Left Hand

Please Note: The 22/31 barrel does not fit Gen 5 models.

The 23/32 barrel will fit in Gen5 models and function to enable you to shoot 9mm ammunition.

Are you looking for better accuracy and higher velocity? Of course you are! Our Double Diamond Premium Barrels are manufactured in the USA and are designed to deliver all that and much more.

Each Double Diamond Precision Barrel is subjected to strict quality control processes to insure quality and reliability.

• Made in the USA by men who shoot, understand and appreciate firearms
• Will handle lead, jacketed or plated ammunition
• Aggressive and attractive crown - looks great, shoots better
• Mirror polished improved feed ramp insures reliability
• Mirror polished chamber and bore increases velocities and improves accuracy
• Precision machined from heat treated, certified, stress-relieved 416R stainless steel
• Fully supported, polished chamber is reload friendly
• Tighter fit than factory spec dimensions
• Match Grade broach cut rifling and deep target crown
• Fits Glocks Gen 1-4 (will not fit Gen 5)

Factory warranty will replace any barrels or barrel accessories which are found to have manufacturing or material defects. Customer modifications or the use of reloaded ammunition will void this warranty.

Please note: In-stock availability of our GSPC barrels may be limited. If your order is time sensitive, we recommend contacting us to verify quantities.

Not available for export outside the United States.

Barrels may only be returned if they are unused and in resellable condition. If the item is defective — ie, does not function — we will accept a return within the 30-day period only.

Order Online or Call Toll-Free: 1-800-601-8273
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Ratings & Reviews

8 reviews

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A # 1 Product


Retired with a Gen 3 Model 32 .357 sig. service weapon. It killed on both ends, ordered the Double Diamond 9mm conversion barrel and dropped it down to a 9mm.

Gun works flawlessly and the teeth have been pulled from that old .357 sig monster not to mention the 9mm ammo is dirt cheap.

Great perfect drop in fit.


Had one worked flawlessly until the she devil ex sold it. Ordered another. This barrel is drop in perfect transforms my model 22 40 cal to a model 17 9mm without any other changes. Great accuracy. Or I wouldn't be getting an other .

Great barrel


Very nice conversion barrel. Works flawlessly and gives the gun a new look.

More than satisfied


Installed SKU: 1012-STS-A27 9mm conversion barrel on my .40 S&W caliber Glock 22. Almost 500 rounds thru it without a single malfunction. Surprising the 9mm shot to the same point of aim as the .40 caliber. Average group at 7 yards is 3/4 inch.

Perfect Fit


Beautiful barrel! Dropped in perfectly! Shoots laser straight! Made my Glock 23 enjoyable to shoot again!

Excellent choice!


Ordered the Stainless Steel version for my G23 and it ran right out of the box. Direct replacement, no issues. I put oil in the factory suggested locations and ran 100 rounds immediately. No issue no hiccups. Dead on accurate. I already had the black yikes connector and the 6lb trigger return spring installed and man it is a lot of fun to shoot.

Quit thinking about it, just buy it. You'll love it.


Took the old barrel out slid the new one in and bam it fires 9mm, simple as that. I had one jam after firing the 19th shot trying to eject. Maybe break in period? Haven't had an issue since shot 150 rounds out of it now.
It does get caught on the slide release when installing it- but if you hold it down slightly the barrel will clear it and the slide slides on no problem.
Accuracy hasn't changed one bit
I would 100% buy again

Glock G23 gen 4 .40 S&W to 9mm conversion


Double Diamond premium conversion barrel for Glock G23 gen4.
Just received the DD barrel and installed into the G 23 .40 s&w glock and purchased the glock 9mm g19 mag.
No other mods. Yook to the range and shot 50 rounds of S&B 115 1nd 124gr ammo. NO FTF or FTE or stove pipes or jambs. Worked flawlessly, very pleased with this conversion from 40 to 9mm.
So Now I have 2 glocks, shootin 9mm at range and .40 S&W for EDC.

Inspected the barrel befor install and it was finished beautifully. no nicks, scratcjes or dents and the feed ramp was super polished, so smoooth feeding. Love being able to shoot .40 and 9mm from same g23. This gen 4 G23 has been perfect fron when it was nes.

Also less muzzel rise as the slide for the .40 g23 is heaver than the g19 9mm slide .
Great satisfied customer.
Best to you guys At GS.