US Tactical Systems, a Versa-Pod company, recently introduced their Back-up Twenty, a full-length fixed buttstock for AR-pattern rifles with a little windowed compartment for housing a spare 20-round magazine.
Made from Dupont Zytel polymer, the construction look sturdy without being much bulkier than a standard full-length buttstock. The window is a nice touch that lets you visually confirm whether or not there’s a magazine inside, although you’d be hard-pressed not to notice with the added weight.
The design is more for compact, low-profile carry of a spare magazine, as opposed to having a one close to the magwell for a fast reload. In order to get the magazine out you have to unlock and rotate the buttpad out of the way and engage the standard magazine release on the side. But if you’re hunting or backpacking, or just want to know that your gun always has an extra 20 rounds in it no matter what situation you’re in, it’s perfect.
You don’t have to be a survivalist to appreciate the design. You never know when you might want your rifle at your side and who knows how many, if any, extra magazines you’ll be able to take with you. It’s a little on the expensive side at $200, but there are more than a few stocks that cost more and do less, and even fewer buttstocks that carry a spare mag for you.
There is the FAB Defense GL-MAG M4-inspired telescoping buttstock. That one is smaller, a little lighter, and drops the magazine right into your hand for fast reloads. The downside is that it will only carry a 10-round magazine flush; you could carry a larger magazine but it will hang out the bottom. The Back-up Twenty also offers better protection against the elements, and while it’s not waterproof, it’s designed to keep dirt and dust away from your magazine.
However, the GL-MAG firmly wins in the price department. At about $125, the Israeli-made magazine-carrying stock is more wallet-friendly.
In the end, while they do the same thing, they do it in such different ways that it’s difficult to make a strict comparison. The Back-Up Twenty looks like it only works with standard 20-round magazines; if you have aftermarket polymer mags they may not fit. Take that into consideration.
Finally, the Back-up Twenty comes with a standard integrated sling loop. (The GL-MAG has quick-detach sling points on both sides. Decisions, decisions.)