High-Cap AR Mags

The Beta C-Magcan help you gain true fire superiority. Photo…

The Beta C-Magcan help you gain true fire superiority. Photo courtesy Beta Outdoors. Photo courtesy Beta Outdoors.

A magazine is generally a place to store ammunition. When speaking of rifles, pistols and shotguns, a magazine is for storing more cartridges ready to be fed into the gun’s chamber. Such magazines may or may not be detachable. Tubular magazines are one example of a non-detachable magazine, as seen on many shotguns and a number of rifles. More commonly, we think of detachable magazines when someone mentions magazines. Mistakenly, magazines are sometimes referred to as “clips,” but while clips charge magazines, they are not themselves magazines.

U.S. military rifles have shown a steady increase in magazine capacity. Single-shot rifles have transitioned to rifles with 5-round magazines, to 8-round magazines, and, finally to 20-round magazines in both the M14 and M16 rifles. Until pitted against the AK-47, a rifle using 30-round magazines, the 20-round M16 magazine served well. When you begin to receive incoming rounds, you want a lot of bullets outbound to gain fire superiority. The 20-round M16 magazine was replaced by a 30-round magazine to match the 30-round AK magazines.

Higher-capacity magazines are available for the M16 and variants. Some triple the standard 30-round detachable box magazine. Most raise the capacity to around 45 rounds, a 50 percent increase.

Bigger Problems?
Some problems come with increasing the magazine capacity. One is length. Extending the magazine to hold more cartridges makes it longer. The 30-round magazine already interferes with a low prone position or shooting off the bench. A 20-round magazine can be useful for prone or bench use.

Second, though it may not always be a drawback, is weight. More ammunition equals more weight. The 5.56mm cartridge is not the heaviest round, but the weight does mount up. If you try to carry as many higher-capacity magazines as you would with 30-round mags, it will be heavier. The added weight will absorb more recoil and stabilize the gun when fired in full-auto or burst mode.

Higher-capacity magazines may also be harder to seat in the rifle. The added spring pressure, needed to reliably lift the column of cartridges, will mean it is harder to lock the magazine in place against a closed bolt carrier. Normal recommendations are to use the higher-capacity magazine as the primary, and reload with 30-round boxes.

Special Applications
Many of these magazines are not intended for combat. They are intended to enhance competition shooting games. Like car racing, competition shooting proves the concepts that may later become the norm.

The highest-capacity magazine currently available is the Beta Company’s C-Mag. It’s been around a while and has been used by the military. It has proven reliable and capable. It avoids the long length problem by using twin 50-round drums.

With two 50-round drums, one to each side of the central mag tube, the short length, top to bottom, allows prone or bench use and balances the weight evenly. Since pushing two columns of cartridges together creates friction, graphite lube is recommended for best results.

The Beta C-Mag has an elegance and panache unmatched by the various box magazines. When you need a lot of ammunition ready to go, the Beta C-Mag will deliver. Long-term storage loading is not a problem with the Beta, either.
Beta offers two loading tools depending on your needs. The Personal Loader loads loose cartridges and the Speed Loader uses stripper clips to load the magazine. The Personal Loader was used here and worked well.

SureFire’s quad-stack magazines. Photo courtesy SureFire.

A New Take
SureFire has recently announced two magazines for military applications. They have developed 60- and 100-round quad-stack magazines. The AR receiver limits the portion of the magazine entering the gun, so the top of the SureFire magazines tapers to a double column at its upper portion. Outside the receiver, the SureFire expands to a four-column cartridge stack. This packs a large number of rounds in about half the space (vertically) of the standard two-cartridge column.

To be sure, the SureFire magazines still have extended length, but for a box magazine, it’s about as compact as you can get for the capacity.

Load Comments
  • Guy Neill

    Thanks for the comments.

    Several of the manufacturers did not respond to my inquiries while others, I admit, did not come up in my efforts to seek out those available.

    I’ll continue to try to contact the various manufacture’s and, hopefully, be able to provide a follow-on article with those not already covered.

  • J Hughes

    I just ordered that Nordic Components Pmag extention kit and a 30rd Pmag. Probably gonna krylon the whole thing OD green. Too cheap to duracoat a magazine.

  • Bill Johnson

    You state that “The highest-capacity magazine currently available is the Beta Company’s C-Mag.” I would urge you to research a little better and you will find out that ARMATAC (http://www.armatac.com/) has been in business for quite some time and have been making quite possibly the best Hi-Cap mag of 100 or more rds. for years now! Their CL-Mag is a 150 round rotary mag that requires NO LUBE EVER!! Please check them out! I wish thagt their discontinued models made of all billet aluminum were still being made!!

  • J Hughes

    And DPMS offers a 45rd magazine, not a 47rd magazine.

  • J Hughes


  • J Hughes

    CMMG does not list any such 45rd magazine on their website. Please correct your article.

  • Scarlighter

    There are also Armatac, MWG and XS-Products with their High-Capacity Magazines, and the largest for a 5.56 AR is the Armatac SAW MAG (150 Rounds).