Home - Volume 3 (2008) - Issue 1 (Winter '08) - Pistol Review: STI Guardian 9mm

STI Guardian 9mm

A Gun Test by Steve Clark (Rio Vista Slim, )

I began a particular gun test (over a year ago) by stating that I'm an "opinionated old curmudgeon". Nothing has changed. Thirty-seven years of legally buying handguns allows me the advantage of having preferences, and I exercise that right. Although a multitude of guns passed through my hands over the years, I lament very few of the ones I no longer own. I DO cherish the ones I have now for several reasons. First and foremost, I deliberately selected the pistols and revolvers in my modest collection. Maturity has tempered the "spur of the moment" indulgences of my youth. Familiarity with design, reliability, and function led to the conscious purchase of weapons I not only wanted, but knew I would shoot a great deal. I KNOW what worked in the past, and bought the guns based on my needs, the manufacturers' reputations, and the intangible quality of "feel".

Caliber selection is also an area where I display an opinionated attitude. Large caliber semi-automatic pistols are what I choose to own (i.e. .45 ACP). I have gone on record several times concerning my dislike of 9mm semi-automatics. While there is nothing wrong with the 9mm, I will spend my money on pistols chambered for the .45. Likewise, I will no longer relinquish my hard-earned funds for any semi-auto not based on the 1911 platform. This is in no way an indictment of any other type of pistol. It is merely a personal choice, and I am most comfortable in making that choice.

Finally, I will not buy a 1911 with anything shorter than a 4 inch barrel, and prefer the true Commander length of 4.25 inches in my personally owned weapons. My general distain for the ultra small 1911s is well documented. While I have been most fortunate to test some very reliable short-barreled pistols, I choose not to own one.

Why all of this "up-front" opinionated drivel, you ask?

The answer is quite simple. I have tested a couple of pistols for the M1911.ORG E-zine which I would choose not to buy! I have been honest with my reviews, above board with my testing protocol, and as objective as possible to the particular niche into which any evaluated gun falls. But, were it not for the testing, some of these same guns wouldn't have gotten a second glance from "yours truly" at a gun show or on a dealer's shelf.

So, based on these criteria, how does the STI International Guardian 9mm fit into the grand scheme of things (ala Rio Vista Slim)? A 9mm (minus) 1911 (plus) on an Officer-sized frame (neutral) with a 3.9 inch barrel (minus) sounds like a natural candidate to be ignored and left to someone else's collection. Right?

Let's take a look and see!

Since 1994, David Skinner has been an integral part of the expansion of STI, and in 1997 completed his purchase of the company, renaming it STI International. In addition to their exceptional line of modular framed 1911s, the folks at the Georgetown, Texas based company have an extensive array of single and double stack pistols, parts, and accessories for the discriminating shooter.

On December 9, 2006, STI International announced the introduction of two new 1911 single-stack pistols to their growing line-up. The STI Escort (previously reviewed here) and the STI Guardian are chambered in either .45 ACP or 9x19. The subject of this gun test, the STI Guardian, is chambered for the 9x19 (9mm Luger or Parabellum) cartridge.

Both the Escort and the Guardian were introduced to the press at the 2007 SHOT Show in Orlando, Florida. Several months passed before either was available for review and evaluation.

The Pistol

As stated above, the Guardian sports a 6.5 inch (165.1mm) stainless steel Commander-style slide mounted over a blued carbon steel Officer's frame. The pistol (wrapped in sealed plastic) is housed in STI's black clamshell foam-lined box. Included in this box are the owner's manual, Recoil Master take-down tool, a package of desiccant, and a small hex wrench to be used if adjustment of the trigger over-travel screw is desired.

Picking the pistol up from the counter at Bill Lamb's Great Guns in Burleson, Texas presented me with the first of several surprises. Although I had read the Guardian was equipped with an Officer's frame made of steel, the heft of the gun seemed much more than the advertised 32.4 ounces (1,007.75 grams). That misconception is based on my extensive testing of aluminum-framed pistols of late. The Guardian balances well in the hand, and initial manipulation of the safety controls were satisfyingly effortless.

The STI Guardian has a stainless steel, flat-topped slide, and sports STI rear cocking serrations. The left side of the slide is roll-marked "STI Guardian", while the right side features the State of Texas STI logo. The flats of both sides of the slide are polished. The top of the slide, as well as the spaces between the serrations are treated in a matte finish. The sights consist of STI's excellent, three white dot Tactical Adjustable Sight. The 3.9 inch (99.06mm) STI Bull Barrel is ramped and fully supported. As with the previously tested STI Escort, the Guardian utilizes the STI Recoil Master Guide Rod and spring assembly. The ejection port is lowered and flared, to aid in the ejection of spent cartridge casings. This slide is lightly de-horned, as is the blue steel frame.

This photograph shows the rear of the slide/frame assembly, featuring the serrated face of the rear sight, and blued extractor within the stainless slide.

The "business" end of the STI Guardian, showing the excellent fit and finish of the muzzle area of the pistol.

The slide-to-frame fit is well executed on the Guardian. There was no perceptible movement between these major parts, when the pistol was in full battery. While tightly fitted, the slide to frame movement is smooth, and the rear slide serrations allow a good firm grip to be maintained when cycling the action. As noted above, the blue extractor presents a contrast to the stainless steel of the slide, while also complementing the blue rear sight.

Moving to the blue steel frame, STI's attention to detail and customer feed-back becomes apparent.

The upswept beavertail grip safety utilizes a palm swell for aiding in the disengagement of this safety.

The checkered cocobolo wood stocks emblazoned with the STI initials complement the appearance of the gun, and are perfectly matched to the officer-sized frame.

The front strap of the Guardian is stippled in STI's exclusive pattern. The grip was quite secure, even during rapid fire drills, but not so abrasive as to cause hand discomfort.

The single thumb safety is of the extended variety, with a slight downward angle that makes engaging and disengaging this safety particularly easy. I have no use for thumb safeties that won't positively click into place, up or down, with just thumb pressure. I have not encountered an STI safety that failed to satisfy my needs.

The STI thumb safety in the engaged position.

This photograph illustrates the flat mainspring housing. This unit is constructed of a nylon polymer for lighter weight.

The Metalform stainless steel magazine fits flush in the Guardian's frame, and the magazine well is slightly beveled for easier reloading. This magazine holds 8 rounds of 9mm ammunition.

The trigger on the Guardian is STI's Long Curved Trigger. This unit has a trigger bow EDM cut from stainless steel wire, with a glass-filled nylon polymer trigger face. There is also a set screw for over-travel adjustment. This trigger consistently measured 4.5 pounds (2,041.17 grams) during dry firing and live fire exercises, as measured by my RCBS Trigger Pull Scale. The Commander hammer, strut, disconnector, sear, ejector, extractor, and sear spring are all STI components, and are hand fit to each pistol at the company's Georgetown, Texas facility.

While admittedly not a fan of plastic on my personal 1911s, I must admit a growing fondness for the feel of the STI Long Curved Trigger. This trigger is very consistent, feels good when firing, and resets quickly for follow-up shots.

Overall, the frame of the Guardian is a fine example of the care the STI gunsmiths show for each of this company's guns that I have observed and shot. There are no tool marks visible anywhere within the frame, or the interior of the slide.


After removing the magazine and checking to be sure the pistol is completely unloaded, cock the hammer and move the slide to the rear, aligning the take-down notch on the frame with the rear of the slide stop. Press the opposite (right side) portion of the slide stop pin, and remove the slide stop. The slide can then be removed from the frame by moving it forward, off the rails.

(Caution: Eye protection is recommended for the next portion of the disassembly.)

Turn the slide over, exposing the bottom of the barrel and the STI Recoil Master guide rod and spring assembly. Using your thumb, the guide rod head is pushed toward the muzzle of the pistol, compressing the recoil springs. When the system is at full compression, the Take Down tool (provided with the pistol) is inserted between the head of the guide rod and the front of the spring tube. The captured system is then removed by pulling the guide rod head towards the rear of the slide. The Take Down tool will have to be rotated to clear the barrel link, but this is easily seen and done. Once the Recoil Master guide rod and spring assembly is removed, the barrel can be removed toward the front of the slide.

The STI Guardian is not equipped with a firing pin safety mechanism, so further disassembly is exactly like that required with full size 1911 type pistols.

Reassembly is in reverse order, being mindful to have the Take Down tool positioned correctly to clear the barrel link, and fit through the opening in the muzzle area of the slide. Insofar as I had already been exposed to this disassembly procedure with the STI Escort, field stripping was easily accomplished. For the novice, it should become second nature after a couple of tries.

Shooting Impressions

The weight of the STI Guardian is ideal for defensive simulation type shooting. Whether firing controlled pairs, Mozambique drills, or engaging multiple targets, the Guardian handles all with ease. For these exercises, I varied the distance between 5 and 10 yards (4.57 to 9.14 meters). When I was able to do my part, the pistol placed all shots exactly where aimed. Only slight variations in elevation were noted when using some of the hotter, lighter weight jacketed hollow point factory ammunitions. Since the gun was shooting dead-on with the Federal American Eagle 124 gr. full metal jacketed rounds, I did not adjust the sights during these drills.

Unfortunately, the ever-changing Texas winter weather made the accuracy and chronograph portion of the tests a little harder to accomplish. I was able, however, to get two fairly decent days in which to chronograph the various factory loads I had on hand, as well as measure the accuracy of this pistol when fired at targets 25 yards (22.86 meters) downrange.

It is important to note that M1911.ORG normally tests handguns with barrels of less than 4.25 inches at a maximum range of 15 yards. This is done because we feel these shorter barreled pistols are primarily intended for self defense, and the consumer public needs to read realistic data based on those criteria. However, my initial range tests with the Guardian indicated a degree of accuracy that demanded the 25 yard range.

These published data were recorded on the second day of testing. Ambient temperature was 44 degrees Fahrenheit (about 7 Celsius), with a relative humidity of 41%. Winds were out of the north at 10 to 12 miles per hour, and the sky was clear and sunny. The gun was fired from a two-handed padded rest, from a stationary bench.

During my shooting tests, I fired 200 rounds of the Winchester White Box 115 gr. FMJ ammunition, 150 rounds of the Federal American Eagle 124 gr. FMJ, and 40 rounds each of the Remington, Speer, and Federal jacketed hollow point ammo. There were no malfunctions of any kind during these tests, and the gun was only wiped down occasionally between firing sessions.


I began this pistol review with a couple of personal disclaimers. While I admit to owning one 9mm pistol, I am not particularly fond of the caliber. I tend to "make a hole, and make it Large!" The STI Guardian has done a lot to change my mind about things.

The all steel construction of the gun makes shooting it a very enjoyable experience. Hitting precisely what one aims at is an added benefit. Recoil with this pistol seems practically non-existent. Granted, the .45 ACP is the lightest recoiling caliber that I normally play around with, alternating between my 1911s and my .357 Magnum and .44 Magnum revolvers. But that might be the point here. The 9x19 is one of those rounds that encourage lots of practice, not only because of the lessened recoil and accuracy, but the bonus of cheaper ammo as well. Modern jacketed hollow point ammunition zips along at quite an impressive pace (see chronograph table), and "reported" expansion has been good in a variety of tested substances.

The Guardian is one of the best balanced pistols I've ever shot. It naturally points in the manner loved by all who appreciate the 1911 platform. The weight is distributed in the hand in a way that makes rapid fire at multiple targets quite easy.

The white 3 dot Tactical Adjustable Sights performed as STI intends, and although I didn't utilize the adjustment feature on this test, the previous test of the STI Escort showed these sights to be easily and accurately fine tuned to any particular load or bullet weight.

The trigger on the Guardian is so good, and so predictable, I am going on record as endorsing this type of trigger to anyone in the market for an STI gun, or anyone else looking for an excellent replacement trigger. Granted, I have not subjected any of these triggers to an extended test, but I am confident that these units can stand up to hard use.

STI claims the Recoil Master system is designed for softer recoil, leading to faster follow up shots on target. My tests reveal that this is probably a true statement. But my personal preferences lean toward more conventional recoil spring/guide rod arrangements. I've never liked to use extraneous "do-dads" to field strip my guns, and my ever increasing arthritis makes the disassembly of this pistol painful. I appreciate the engineering that goes into each Recoil Master, and realize that shorter barreled pistols require a different recoil spring assembly than the 4.25 and 5 inch guns. I just wish some of them weren't so hard for us "old" folks to operate. (Okay, I admit that shooting a .44 Magnum doesn't do me any good either, but my finger strength is the issue here!)

While I admit to a general dislike for multi-colored pistols, the stainless slide complements the blue steel frame. I prefer the two-tone look of the Escort over that of the Guardian. Once again, this is a personal expression of opinion, and does not detract from the STI Guardian's mission.

STI International is one of those rare companies that take their customers seriously. They stand behind their products, and listen to what the gun buying public has to say. While I don't participate in competitive shooting sports, I have fired several of STI's race and competition pistols, and found each one to be excellent in fit, finish, and function. The STI Guardian displays all of those positive attributes, and I heartily recommend this gun to anyone looking for a dependable, concealable 9mm 1911.


This test would not have taken place without the invaluable assistance of Jay Dunlap. Jay made sure that the M1911.ORG E-zine received both test pistols in as short a time frame as was possible. His patience with me, and the realization that you can't reliably test a pistol in the rain, contributed to a longer-than-usual test, but one that showed the true potential of this fine weapon. Thanks for everything you've done, Jay, and please convey my thanks to Dave Skinner and the staff at STI International as well.

Bill Lamb is a friend, a fellow gun lover, and a professional in every sense of the word. Were it not for his help (and the help of his lovely daughter Haley), I would be unable to complete any of the numerous gun tests and reviews I've been fortunate enough to participate in. I can't say enough good things about Great Guns in Burleson, Texas, other than to recommend this gun store and Bill Lamb to anyone needing firearms or accessories. Thank you Bill!

Finally, my heartfelt thanks go out to the folks at Competitive Edge Dynamics. Your CED Millennium Chronograph is an invaluable tool, and a joy to use.


STI Guardian
Caliber: 9mm (also .45ACP)
Frame: 1911 Officer Frame, STI stippled front strap, undercut trigger guard
Stocks: Checkered cocobolo grips panels with STI lettering
Slide: Stainless steel Classic Commander Flat Top with STI rear cocking serrations
Trigger: STI Long Curved Trigger
Barrel: Bull Barrel, 3.9 inches, ramped and fully supported
Safeties: STI High-Ride Beavertail Grip Safety, single sided thumb safety
Guide Rod: STI Recoil Master
Sights: 3 Dot (white) Tactical Adjustable Sights
Overall length: 7.5 inches (190.5mm)
Weight (empty): 32.4 ounces (1,007.75 grams)
Finish: Stainless steel slide with polished sides, blue steel frame
Suggested Retail Price: $1,024.00 U.S. Dollars

You may discuss about this pistol, ask questions or in general discuss about this review, in this thread in our Forums Site:




STI International
114 Halmar Cove
Georgetown, TX. 78628

Tel: 512-819-0656
Fax: 512-819-0465

Email: sales@STIGuns.com
Web site: http://www.stiguns.com


Competitive Edge Dynamics USA
P.O. Box 486,
Orefield, PA 18069-0486

Orders: (1) 888-628-3233
Phone: (1) 610-366-9752
Fax: (1) 610-366-9680

Email: info@CEDhk.com
Web site: http://www.CEDhk.com

Home - Volume 3 (2008) - Issue 1 (Winter '08) - Pistol Review: STI Guardian 9mm