Kahr PM45—The Lightest, Most Compact .45 ACP

Tactical Response, July/August 2008, p. 131 - 134
By Steve Tracy

A lightweight backup gun in an ankle holster.

Kahr Arms entered the firearms industry with a single purpose. Its goal was to make the best off-duty / backup / concealed carry pistol available in a major caliber. Founder and CEO Justin Moon's K9 series of double-action-only, stainless steel 9mm pistols were more compact than any other firearm available from the competition. When it came to ease and comfort for concealed carry, the thin width of the Kahr trumped other 9mm handguns. Kahr followed up its success with the addition of lightweight polymer frames, .40 S&W caliber models, and “micro” versions having even shorter heights and lengths.

Today the Worcester, MA gun manufacturer has brought out the lightest, most compact .45 ACP pistol available. The new PM45 offers big bore backup or concealed carry power in an amazingly small package.

Kahr Arms

Moon founded Kahr Arms in 1993, a year after he graduated from Harvard with a degree in economics. The manufacturer's parent company had been utilizing Computer Numeral Control (CNC) machine tools since 1981. In 1986, it began contracting machining and assembly services for several high-tech fields, including aerospace, automotive and electronics. Moon was an avid firearms enthusiast. He believed a compact 9mm semi-automatic pistol could be made that was smaller than anything else offered on the market. He also had access to his business' CNC shop and top-notch engineers, which provided him with the ability to make his dream become a reality.

One method for success, upon entering a competitive and crowded market, is to offer a product that no one else can match. Moon secured six U.S. patents, which allowed his striker-fired, double-action-only (DAO), Browning locked breech pistol to be smaller than any others.

The most obvious patent is the offset barrel feed ramp. When the feed ramp is left instead of center, it allows the trigger mechanism placement to be higher, which in turn provides for a higher handgrip. Felt recoil is reduced when the shooter's hand is closer to the centerline of the bore. The self-cleaning extractor is also closer to the chamber, which allows the entire gun to be thinner compared to the competition.

On its Web site, Kahr's advertising mascot is named Bubba Blitz, He is a small dog with a big set of teeth and his motto is “Bite Size, Big Bite.” He epitomizes the company's direction and its aggressive marketing campaign. Kahr does not make revolvers, target .22LRs or full-size pistols.

Its credibility was established with the small K9 9mm pistol, and the focus remains in this arena, Kahr stepped up with the .40 caliber K40, and now Kahr presents its biggest set of teeth, bringing forth a .45 caliber pistol.

The PM45 (for Polymer Micro .45 caliber) appears very similar to the previous Kahr family of pistols. The gun does, indeed, feel small. The officers who checked it over made the same statement, “That little polymer gun is a .45? That's really going to kick,” I had reservations about firing the tiny .45 as well. Flashbacks of shooting full house .44 Magnum loads flooded my brain.

My anticipation turned out to be unfounded. I was pleased to find that, despite its 19.3-ounce weight (unloaded with magazine), the PM45 was actually rather pleasant to shoot. This had much to do with the PM45's overall dimensions with a height of 4.5 inches, a length of 5.7 inches and a slide width of only 1.0 inch. Compared to the old standby standard for semi-auto backup guns, the Walther PPK's overall height is just 0.7 inches shorter than the PM45. The PPK's length is actually longer than the PM45 by 0.4 inches, and they are almost identical in width, despite the much larger jump in power and caliber from .380 ACP to .45 ACP.

The length of the PM45's grip contributes greatly to its ability to be fired easily. I have large hands but was still able to securely grip the Kahr's front strap with all three fingers. Kahr did its homework; if the grip were any shorter, it would be very difficult to hold.

Double-Action-Only Trigger

The Kahr PM45 is an excellent choice for off-duty concealed carry.


The Kahr offset barrel feed-ramp, intricately machined slide release lever magazine's metal feed ramp insert, and polymer frame.


Kahr PM45 field stripped for cleaning.


Excellent combat accuracy at 7 yards.


.45 caliber power in a small and lightweight package.

I first learned to shoot using a bulls-eye target stance, firing one handed, My father taught me that accuracy was everything Perfect sight alignment and a super light trigger pull were most important. But my view changed when I became a police officer. Gunfights occur in an instant, and an officer does not have time for a perfect stance. He cannot slow down to let out half a breath and then squeeze the trigger so gently that he doesn't know when the gun will go off.

Combat shooting to save your life is about hitting center mass quickly. I found that the PM45's long, consistent trigger pull actually aided in accuracy. I lined up the excellent white dot front sight with the white vertical bar rear sight. The smooth and light double-action-only trigger is long, but it has no staging. Tritium night sights are available as an option. The PM45 magazine holds five rounds, and the gun can be fired with the magazine removed. The magazines are plasma welded, which prevents stacking jams and provides a tough seam. They are also tumble polished for a surface free of burrs. The magazine's plastic follower has a built-in steel slide stop contact pin. This pin engages the slide stop lever much more reliably than plastic and eliminates wear.

Polygonal Bore

Lothar Walther has been producing match grade gun barrels since 1925. Kahr contracts the company to forge the PM45's 3.14-inch barrel. In place of traditionally cut, land and groove rifling, the PM45 utilizes a polygonal bore, popularized by Glock. This type of twisted rifling has no sharp edges and is purported to give longer barrel life as well as increased velocity and accuracy. The barrel is well made from solid, high tensile strength, proprietary steel billet and incorporates the distinctive offset feed ramp.

Everything about the Kahr shows attention to detail and intricate machining. The slide release lever has an impressive number of complicated machined angles cut into it. Field stripping the PM45 is accomplishing by removing the slide release lever to the left and then moving the slide forward, off the polymer frame. The powerful dual recoil springs are captive on their guide so you don't have to worry about them flying across the room during disassembly, The barrel then lifts out of the slide, and its polygonal bore is easy to clean.

The Kahr is a precision-made firearm with tight tolerances. Its manual states that the PM45 should be “broken in“ by first firing 200 rounds through the gun. At today's ammo prices, that can be a rather expensive proposition, I experienced three failures to extract during the second hundred rounds fired. However, I believe these stovepipes were the result of some older ammunition having slightly corroded brass. These tarnished rounds may have stuck in the chamber walls. A total of 350 rounds of various manufactured ammo were fired through the pistol with no further trouble.

Winchester's 185-grain Silvertips had much less kick than I had anticipated. I felt l could fire them all day long. I was leery that the sharp checkering on the pistol's front and back straps was going to chew up my hand. Instead, it gave me a solid purchase on the gun's grip, just as it was designed to do. Accuracy was impressive as well. It is always rewarding when you keep your sights aligned, complete a proper trigger pull, and then find your bullet placement to be right where you aimed. The PM45 hit the 10-ring on a standard silhouette target hung at 7 yards every time. Speer 230-grain hollow points, as well as Speer FMJ ball ammo, also struck to point of aim.

The right rear corner of the magazine's polymer bumper base does have a rather sharp corner, The heavier hollow points produced the most recoil, and the magazine's corner dug into my palm. That corner could be rounded with a dremel tool to eliminate its painful point.

Several officers with varying degree of shooting skill fired the diminutive .45, automatic. Each began firing with trepidation but finished with an appreciation for the powerful little package. The Kahr's recoil is not as punishing as one would expect. Lighter 185-grain, non +P rounds were actually a pleasure to shoot. The gun's grip angle and length, with the patented feed ramp offset, allows a high grip. The excellent trigger pull combines to make the Kahr PM45 an outstanding backup or concealed carry weapon.

Several 45 Pistols

Kahr offers a lineup of several semi-automatic pistols chambered in .45 ACP. The largest is the TP45, which has a seven-round magazine capacity and a 4.0-inch barrel. The P45 holds 6 rounds and has a 3.5-inch barrel. But the new PM45 is the smallest and lightest .45 ACP available with its five-round magazine and 3.1-inch barrel. Extended magazines are available for all of the .45 ACP models, and they add one more round to their capacity.

Kahr also makes the CW45, which has a six-round capacity and a 3.6-inch barrel. The CW line is less expensive than other Kahr models, CW pistols utilize standard cut rifled barrels and some metal-injected molded (MIM) parts. Pinned polymer front sights and less attractive slide markings and contours help offer a cost savings without affecting overall performance.

The MSRP for the PM45 is $838 with standard sights and $955 with night sights. However, I have seen them sell for up to $200 less at stores, Police officers who favor the potent .45 ACP round for a backup or concealed carry pistol will be well served by the compact, thin, and well-engineered Kahr PM45.

Steve Tracy is a 20-year police veteran with 18 years of experience as a firearms instructor. He also is an instructor for tactical rifles, use of force less-than-lethal force and scenario based training. He can be reached at steventracy@hendonpub.com.