Ruger MK III/MK IV 10-Round Magazines: Double the Fun!

Back in 1949, an American institution was begun. William Ruger and Alexander Sturm partnered up and started Sturm, Ruger & Co., which turned into the major gun maker that so many of us have come to know.

Ruger’s very first design was called the Standard Pistol. It had many similarities to the Japanese Nambu pistol and to the German Luger, both used in WWII (and the Luger also in WWI).

Ruger wanted something that regular, working folks could afford. A pistol that was reliable and accurate. To that end, he seems to have succeeded, as they were good sellers and helped to get Ruger on the map. Ruger’s manufacturing techniques allowed him to sell this pistol cheaper than pistols sold by his competition, making it very appealing to shooters. Initially, the Standard, which was introduced in 1949, sold for $37.50.


The Standard kept going strong for decades, being widely popular. Eventually, though, Bill Ruger decided to move forward with some upgrades and the MK series was born.

The MK I started out in 1950 and endured until production ceased in 1982. It added, among other things, an adjustable trigger and target sights. Over the years, various barrel lengths and contours were offered.

In 1982, the MK II was born. It added a slide stop to hold the slide open after the last round was fired. As well, a stainless finish became available. On top of that, various barrel lengths became options, which gave shooters a pleasing selection. Production of the MK II ended in 2004, as the company introduced the MK III series, which continued until 2016.

The MK III featured the addition of a loaded chamber indicator, it was drilled and tapped for a Weaver scope base, and it had a magazine disconnect to prevent the pistol from being fired with the magazine removed. One of the most significant changes was that the magazine release was moved from the heel of the grip to behind the trigger guard (where they’re typically located on pistols). As with all the other MK series, various barrels and finishes were offered with the MK III, which made it appeal to a wide range of shooters.

Ruger MK III Target Competition Model in .22LR.
Extra magazines make shooting sessions more fun. This is the Ruger MK III Target Competition Model in .22LR.

Finally, the MK IV was introduced in 2016. In this series is the 22/45 model, with a grip that replicates that of the 1911. And it really does feel like a 1911!

Up until the MK IV, field stripping the MK series was a major hardship. In fact, many shooters dreaded it so much that they didn’t clean their pistols! The MK IV introduced a takedown button, which drastically simplifies the field stripping procedure and eliminates that problem.

Ruger MK III & IV Magazines

This brings us to the magazines that are used for the MK III. These magazines are marketed as fitting both the MK III and the MK IV. I do have a Ruger MK IV 22/45 pistol, and I assumed that these magazines would fit my 22/45. However, they will not; they are for the standard MK series. The base plates for the 22/45 pistols are longer. The rest of the magazine looks identical to the standard MK III and IV magazines, but the 22/45 models need that longer base plate and these have the shorter base plate. Bottom line, they will only fit the standard models, not the 22/45 models.

The Value 2-Pack of Ruger factory magazines is a great value and adds to the fun of a range session.

Magazines that fit the 22/45 models are available, however, for those who are interested.

Upon looking closely at these magazines, the quality is evident. They are constructed of stainless steel that has a sliver, matte finish. Each magazine has a polymer base plate. The magazine follower is also polymer, which helps a lot with lubricity; polymer on steel seems to just glide effortlessly. That goes a long way in adding to the reliability and feeding.

Inside the magazine is a steel wire spring. Ruger magazines tend to last a very long time, with examples commonly lasting for decades.

On the left is the magazine that fits the 22/45 models; it has the longer base plate. On the right, with the shorter base plate, is the model that fits standard MK III and MK IV pistols, which is the subject of this article.

A really nice aspect of these magazines is the Reloading button on the side. It’s a round tab or button that the user grasps and pulls down. It compresses the spring and brings the follower down, which allows bullets to be fed into the top of the magazine. It serves its purpose very well, relieving the spring tension, which makes loading the magazines easy. These are among some of the easiest magazines you will ever have the pleasure to load.

ruger MK III magazine reloading button
The reloading button can be seen near the bottom of the magazine on the side. It makes loading the magazine easier.

The fact that these come in a 2-Pack makes them more economical to purchase. GunMag Warehouse sells the pack of two magazines for $42.99 at the time of writing. That’s a good price, considering these are factory OEM (Original Equipment Manufacturer). I normally buy OEM magazines for all my firearms, having found that OEM typically is the most reliable option out there.

The Test Gun

Because these magazines did not fit my personal 22/45, I borrowed a friend’s MK III Target Competition Model .22LR pistol to test them out.  The pistol has a slab-sided bull barrel that is 6.88 inches long. The weight of the pistol is 45 ounces, so it’s pretty hefty. The stainless, matte finish is not only attractive but also very durable.

What a treat it was to shoot that pistol! The accuracy level was outstanding, with just about zero muzzle flip. The grip, which has a thumb shelf, is also luxuriously comfortable. All in all, Ruger put together a tack-driving pistol that’s fun to shoot.

For this shoot, most of the ammo used was CCI Mini Mag 40-grain solid rounds with copper plating. Of course, the magazines functioned perfectly. They locked into place readily and fed with 100% reliability. Ejection was also positive. As mentioned, loading the magazines was made easy due to the reloading button on the side.

Shooting the MK III Target Competition pistol from Ruger. Low muzzle flip and high accuracy made it fun.

Having some spare magazines along for the ride enhances the shooting experience. For example, we shot the Ruger MK III on a very cold, windy day. The temperature was around 30° F and that wind cut like a knife. It wasn’t the sort of day in which most people relish loading magazines in the great outdoors. Finger-numbing cold is not conducive to fun times while stuffing rounds into magazines. Pre-loading a handful of magazines was the order of the day here!

Ruger MK III Value Pack — Worth It?

The 2-Pack of MK III/MK IV magazines is a perfect addition for the Ruger pistols. With the 2-pack, they’re more economical than purchasing one magazine at a time. We can never have too many magazines, so I could see picking up a couple of these 2-packs. Extra magazines make a shooting session far more pleasurable.

The Ruger factory magazines have proven to have perfect reliability, and their durability is excellent.

Jim Davis served in the PA Dept. of Corrections for 16 ½ years as a corrections officer in the State Correctional Institute at Graterford and later at SCI Phoenix. He served on the Corrections Emergency Response Team (CERT), several of those years as a sniper, and also the Fire Emergency Response Team (FERT). For 25 years, he was a professional instructor, teaching topics including Defensive Tactics, Riot Control and Tactical Operations, Immediate Responder, and cognitive programs as an adjunct instructor at the DOC Training Academy. He was then promoted to the title of corrections counselor, where he ran a caseload and facilitated cognitive therapy classes to inmates. His total service time was close to 29 years. He was involved in many violent encounters on duty, including incidents of fatalities. He is a dedicated Christian and attributes any skills that he has to the glory of God.

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