Ruger Four-Inch 357 Magnum SP101 Double-Action Kit Gun


by Jeff Quinn

photography by Jeff Quinn & Boge Quinn

December 8th, 2011


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Ruger's new SP101 357 Magnum revolver with 4.2" barrel and adjustable sights.



SP101 has a very comfortable, yet compact, grip.









The cylinder is plenty long enough for the longest 357 caliber bullets, such as the 200 grain hard-cast bullets loaded into this Cor-Bon ammo.






It has now been twenty-two years since Ruger introduced the dandy little SP101 compact revolver. Unlike most small five-shot revolvers, the SP101 is made primarily of stainless, giving the handgun enough heft for easy controllability, yet it is still compact enough for comfortable carry. The little SP101 is one of the most durable revolvers ever made. I once made a huge mistake in handloading for a SP101, using a powder that I should not have tried. I had to beat open the cylinder with a hammer, and use a punch to hammer the empty case out of the chamber. That load would have destroyed a lesser revolver, but the little SP101 held together, and I still use that dandy little revolver to this day. I go to a lot of gun shows, but seldom see a used SP101 for sale. Those who buy them tend to keep them, and for good reason. The SP101 is reliable, compact, accurate, and built to last forever.

The SP101 has always been marketed as a compact defensive revolver, and it serves that role very well. However, now available with a 4.2 inch barrel and fully-adjustable sights, the role of the SP101 has expanded greatly, and in this configuration, it is an outstanding hunting and trail gun, filling the role of a great multi-purpose revolver for the outdoorsman.

The new configuration of the SP101 makes it very useful as a compact, general purpose 357 Magnum. The four inch barrel is able to take advantage of the capabilities of the 357 Magnum cartridge much better than can the shorter barrels. The sights on the four-inch SP101 are also a great improvement, with the adjustable rear allowing the revolver to have the practical accuracy needed for field and hunting use. The front sight has a square post profile, with a fiber-optic rod insert, presenting a bright dot for use in low-light situations.

The 357 Magnum SP101 is a good choice as a trail gun for those who need more power than is available from a similar-sized rimfire 22 caliber revolver. The 357 Magnum, properly loaded, has enough power for cleanly taking whitetail deer and similarly-sized game, and will work well also as a defensive handgun against predators, as well as a good defensive handgun for distasteful social conflicts.

The Ruger SP101 carries very well in a good belt holster, such as the Simply Rugged Cattleman shown here. The Cattleman carries the revolver snugly against the body for good concealment, yet makes the handgun readily accessible when needed.

Specifications are listed in the chart below. Weight is listed in ounces. Trigger pull is listed as pounds of resistance, as measured using my Lyman digital scale. Linear measurements are listed in inches. The cylinder length does not include the ratchet star. Height includes the sights, with the rear set at its medium adjustment. DA is the double-action trigger pull. SA is the single-action trigger pull.

Overall Length 9 Inches
Overall Height 4.72 Inches
Weight (Unloaded) 28.8 Ounces
Barrel Length 4.15 Inches
Cylinder Length 1.58 Inches
Cylinder Diameter 1.35 Inches
Barrel/Cylinder Gap 0.006 Inch
Trigger Pull DA 9 Pounds, 9 Ounces
Trigger Pull SA 4 Pounds, 12 Ounces

For accuracy and function testing, I tried every type of 357 Magnum factory ammunition that I had available to me in the SP101. The ammo consisted mostly of high performance ammunition, along with one of my favorite cast bullet handloads that I use as a general purpose plinking and “do everything” loads. This moderate handload uses the excellent Mt. Baldy 173 grain plain base Keith semi-wadcutter bullet with six grains of Hodgdon Titegroup powder. The accuracy of the SP101 was tested using my Ransom Master Series machine rest. The chronograph and accuracy results are listed in the chart below. JHP is a jacketed hollowpoint bullet. SP is a jacketed soft point bullet. DPX is a homogenous copper hollow nose bullet made by Barnes Bullet Company, and loaded by Cor-Bon. This is also the same style of bullet as loaded into the Buffalo Barnes load, but at a different bullet weight. Glaser is a specialty jacketed bullet with a compressed pre-fragmented core. PB is Cor-Bon Pow’RBall. HC is a hard-cast lead bullet. Keith is the aforementioned semi-wadcutter cast lead bullet. Velocities were recorded at a distance of twelve feet from the muzzle, and are listed in feet-per-second (fps). Bullet weights are listed in grains. Accuracy results listed are the average of the five-shot groups fired at a distance of twenty-five yards, listed center-to-center of the widest apart bullet holes in each group. Group sizes are listed in inches. Testing was done on a calm day with an air temperature in the 33 degree Fahrenheit range, at an elevation of approximately 541 feet above sea level, and relative humidity of ninety-six percent.

Ammunition Bullet Weight Velocity Group Size
Cor-Bon HC 200 1108 2.50
Cor-Bon JHP 110 1502 2.10
Cor-Bon PB 100 1661 2.60
Cor-Bon JHP 140 1300 1.75
Cor-Bon DPX 125 1333 2.60
Cor-Bon SP 180 1213 1.88
Cor-Bon JHP 125 1345 1.88
Cor-Bon Glaser 80 1794 3.30
Buffalo Bore JHP 125 1514 1.90
Buffalo Bore JHP 170 1201 2.30
Buffalo Bore JHP 158 1309 1.75
Buffalo Bore Barnes X 140 1552 2.13
Buffalo Bore 38 Special +P Keith 158 1085 1.50
Grizzly Cartridge HC 180 1198 2.50
Handload Keith 173 1067 2.00

The SP101 shot very well, and displayed impressive velocities, especially with certain loads. I particularly like the Buffalo Bore load using the excellent all-copper Barnes XPB hollow nose bullet. This bullet expands well, penetrates deeply, and stays together. From the barrel of this SP101, the 140 grain bullet registered an average of 1552 feet-per-second, twelve feet from the muzzle. For a good all-around load with lower recoil, but still very good performance, I like the Buffalo Bore 38 Special +P load that uses the 158 grain hard-cast Keith bullet. This ammo proved to be exceptionally accurate from the SP101, grouping a cylinder-full of ammo into one and one-half inches at twenty-five yards. As can be seen in the chart above, most ammo tested exhibited very good accuracy, with others delivering average performance. The ammo that delivered the worst accuracy also had the widest variation in velocity spread, and that is certainly no fault of the revolver. I handload most of my ammo, but if sticking with only factory ammunition, I could certainly make do very well with those two Buffalo Bore loads listed above, as they would cover every possible need for such a handgun as this SP101.

This SP101 has a very comfortable grip that is hand-filling, yet compact. The trigger pull in double-action mode is smooth, and the single-action pull crisp. The SP101 functioned perfectly, firing every cartridge. With the heaviest Buffalo Bore high-performance ammunition, the extraction was a bit sticky, but not enough so as to present a problem.

This latest version of the Ruger SP101 is perhaps the best version yet produced in the long life of this excellent little revolver. The gun is reliable, compact, powerful, and weighs almost three-quarters of a pound less than its comparable six-shot big brother; the GP100. The SP101 is no longer just a great defensive revolver, but is now an excellent general-purpose trail and hunting gun. It fills the roll well of what is known as a “Kit Gun”, which is a relatively light, handy, and accurate handgun that can always be at one’s side in the outdoors, while camping, hunting, fishing, or just bumming around the woods. The SP101 has always been a dandy little revolver, but this new version is the SP101 perfected.

Check out the entire line of Ruger firearms and accessories online at

For the location of a Ruger dealer near you, click on the DEALER FINDER at

To order the SP101 online, go to

To order Simply Rugged leather, go to

To order quality 357 Magnum and 38 Special ammunition, go to,, and

Jeff Quinn

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Click pictures for a larger version.




Fiber-optic front sight has a square profile for an excellent sight picture. Rear sight is fully adjustable for windage and elevation.



Simply Rugged "Cattleman" holster works well for concealment and field carry.



Buffalo Bore's load using the excellent Barnes 140-grain copper hollowpoint is an accurate and powerful 357 Magnum load for the SP101.



The SP101 is capable of fine accuracy, as these 25-yard groups fired from a Ransom Rest show.