If you shoot in 3-gun competitions or are just interested in some bolt-on mods for your AR-15 that can add some color and capacity to your magazines, check out the new Magpul Gen3 PMag Base Extensions by Coronado Arms. [Noobs note: a magazine base plate is the piece on the bottom of the magazine that holds the follower, magazine spring, and whatever other goodies your magazine may have inside. A mag base extension is an upgraded version of that plate that “extends” the functionality of the off-the-shelf plate, adding to a magazine’s round capacity. They can also add a personalized (and colorful) touch.] The bases from Coronado are available in . . .
Aesthetics
blue, gold, green, purple, red. If you want something a little more subtle, they also offer them in basic black. Coronado’s extensions are bolt-on accessories that will change the look and feel of your rifle, and magazines quickly and without hassle.
Functionality & Features
One of the primary functions of an extension is to add round capacity to magazines. One of the best ways for shooters to cut time during matches is to limit or avoid reloads. The Coronado Arms PMag Extension adds five additional rounds to your standard PMag, so your standard 30-round magazine just became a 35-rounders. You use the factory magazine spring so the spring is a little “stretched” in these applications. That said, I didn’t have any failure to feed (FTF) issues or instances where the bolt wouldn’t lock back. Everything worked as normal.
Another benefit of the base extension is that it adds a little weight (about 2.6 oz.) to the magazine base. The extra heft can help the magazine fall from the rifle with a little more authority. It may not be a big deal for normal usage, but during competition in which shooters are trying to cut fractions of seconds from re-loads, every little bit helps. For high-speed re-loaders, ensuring the magazine falls reliably and quickly is critical.
Depending on conditions where you shoot, your mag extensions will get a little dinged up, but they’re tough enough to take it.
Also, when carrying extras, the base provides a very positive “handle” to grab on to when reaching for a fresh mag. So you shouldn’t have your hand slip off of the magazine if something gets tied up in your gear a bit. That’s never a bad thing.
Coronado Arms also offers a dual extension (above) that allows you to connect two magazines together and attach the same way as single bases. This works well for really fast mag changes as you simply have to pull the magazine down, move it over an inch or so, and then slam the full mage right back into place. While two full mags hanging from your rifle adds a fair amount of extra weight, it’s definitely a time saver and can help mitigate some recoil. Just make sure it wont interfere with how you’re planning to shoot, because it’s obviously wider than a single magazine and can get in the way if you aren’t used to it.
Fit
The Coronado Arms PMag Bases fit on 20-, 30- and 40-round Gen2 and Gen3 PMags. They do not fit on Gen3 10-round magazines. The 10-round mags are designed a little different and the base will not slide on and off. You could probably shave some material off of the mag and make it work, but if you’re running 10-round magazines, there’s a good chance extending the capacity isn’t legal where you are to begin with.
The extensions fit very tightly so there’s no rattle, wiggle or other movement when installed. You can grab and tug on them and they will stay nice and secure.
Installation
Installation of the base extension is pretty simple. First, remove the existing base plate by pressing in the grey bar on the bottom of the magazine and slide the stock plate backwards off the magazine. Make sure to catch the spring, or it will launch across the room. You will need those parts.
Once you have the Magpul base plate off and the magazine disassembled, remove the gray plastic plate attached to the bottom of the magazine spring. When that is removed, you are ready to put the magazine back together with the new base plate extension.
First, put the magazine follower and spring back into the magazine, making sure they are going in the right direction. Then press the spring into the magazine while sliding the back of the magazine extension (the longer part) on to the magazine. Once that is all the way on, the magazine spring should rest in the bottom of the extension, there is a bevel cut into the extension to help keep the spring in place.
Once you have the larger base potion fully pressed on to the magazine, you can press on the front cover. It should slide into place without too much resistance, but may require a firm press to get the screw hole on the bottom to line up. Once everything is pressed together completely, install the screw in the bottom portion of the extension and tighten. You will need a 5/64 allen wrench for the screw, you can get one, here.
You may have to wiggle things around a bit and give a firm press to get everything together. The extensions are pretty tight to keep them from rattling or moving around. So with anything that is “fit”, you may have to use a little force and make sure things are lined up correctly.
Once you have everything together, you can use the magazine as normal. If you ever need to clean or remove the base plate, simply take out the screw and reverse the process. Quick and easy, and no issue with magazine spring, etc.
Specifications
| Weight (single) | 3oz (2.6oz added to overall magazine weight) |
| Weight (double) | 7.4oz |
| Length | 3.012in (76.52mm) |
| Width (single) | 1.170in (29.73mm) |
| Width (double) | 2.952in (74.99mm) |
| Height | 1.432in (36.37mm) |
| Additional Round Count | 5 |
| Supported Magazines | Magpul Gen3 20, 30, 40-round magazines |
| Material | 6061-T6 Aluminum |
| Anodizing | Type-2 |
| Required Tools | 5/64in Allen Wrench |
Ratings (out of 5 stars)
Price: * * * *
At $30 MSRP, the Coronado Arms base extensions are priced well and in most cases lower than many competitors.
Ease of Installation: * * * ½
Installation of the base plate is easy, though it does require tools. Sometimes this can be PITA on the range.
Durability: * * *
The extension seems to be pretty durable. I haven’t driven over it with a truck, but you probably shouldn’t do that to your magazine anyways. They’ll develop superficial scars pretty quickly, but none of that will affect functionality.
Usefulness: * * * * *
It does all the things you would want from a mag extension. Increased capacity, good look and feel, etc….
Overall: * * * *
They work well, look nicely and are easy to install and maintain. Definitely worth your consideration.