Cain Arms is a small American company who builds innovative products that shooters can afford. My favorite is their Glock 9/40 Magazine (Plus Five in 9mm or plus four in .40) Extensions. They work and you don’t have to sell a gun to afford them.
If you don’t have a trust fund, use a mag well, shoot competition or just want to color code your magazines (I use orange for 9mm, blue for 40 and red for dummy rounds) so you know what they are and who they belong to at a match, the Cain Arms base plates are for you.
They have a strong simple design with a set screw and are made of tough industrial polymer. They pad the fall when you drop them and function well with four or five extra rounds. If you watch the installation video you can’t go wrong. One caveat, if you have old mags with compressed springs, you may need to replace the springs or stretch them. With good springs this won’t be a problem. Don’t be that guy, just get some new springs.
I shot through all three of my mags several times with 22 rounds in my Glock 17. I also cycled dozens of dummy rounds through my red trainer. No issues. They work on all Glock OEM small frame magazines and ETS magazines. There is another model for Glock PMAG GL9 extension.
Glock 9/40 Magazine Extension
- Industrial polymer
- Strong & lightweight
- Adds 4, 5 or 6 rounds
- Maintains USPSA 141mm length
- Glock 17, 19, 22, 23, 26, 27, 31, 32, 33, 34, and 35 mags
- Works with Glock OEM & ETS mags
- Retention screw system
- Made in the USA
- Magazine not included
- Spring may need replacing
$19.99 Get your Cain Arms Goodies HERE
- Free Shipping On All Orders Ships within 1-3 days
- Colors- Red, White, Blue. Black, Pink, Opie Orange, Tiffany Blue, Dark Earth, Olive, Grey
Custom Colors- $24.99 Custom colors must be specified in notes section and generally take an additional week to ship
- Custom Colors- $24.99 Custom colors must be specified in notes section and generally take an additional week to ship
https://youtu.be/HptVXwVtOuc

About Cain Arms
A small 3D printing company based in Salisbury, Maryland, Cain Arms specializes in firearms accessories. They believe that quality does not have to be complicated. Their approach is to keep it simple and keep it affordable.
In his own words:
My name is David Cain. I discovered 3D printing by chance while studying Mechanical Engineering Technology at the University of Maryland. I had designed a lightweight alternative to the bulky and ugly pistol brace and took my design to a local machine shop. The owner had a 3D printer and within an hour I was holding a replica of my design. At that point I was enamored with 3D printing, but I still thought it would be professional to use a mold. After waiting far too long for a functional prototype to be manufactured for me I decided to look into the 3D printing. Using the available Makerbots at school I printed, tested, refined and adjusted my design until I was satisfied that it was industry worthy. I initially wanted to sell on Amazon, but with limited resources and an incredibly difficult Amazon listing process I turned to eBay for all of my preliminary sales. When things began to pick up I designed a website and many other products followed. In fact we have so many design ideas we are constantly on the verge of a new product. We also do custom & design work for anyone and everyone in need of our services. We have done everything from wall decor to Toyota back-up camera mounts to in-dash cell phone holders to sign lettering…I could keep going. I still find myself obsessed with this technology after several years due to its lack of a creative boundary. If you can dream it, we can build it.