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The Ruger’s Seven Shot GP100 327 Federal Magnum is a lot like a really good peanut butter and jelly sandwich. A combination of the proven GP100 revolver and the spiffy .327 Federal Magnum cartridge, together they make a really exceptional firearm. Federal lists the .327 Federal Magnum as a defensive cartridge, which I am sure is very appropriate. However, there is additional potential for use on varmints and small game and for inexpensive recreational target shooting.

Cartridge – Nominal Performance


Muzzle 25 50 100
32 ACP – 71 grain Velocity 900 872 846 798
Energy 128 120 113 100
Trajectory 0 -2.0 -15.2
32 S&W Long – 98 grain Velocity 780 764 749 719
Energy 132 127 122 113
Trajectory 0 -2.9 -20.4
32 H&R Magnum – 85 grain Velocity 1120 1067 1023 953
Energy 237 215 197 171
Trajectory 0 -1.0 -9.4
327 Federal magnum – 85 grain Velocity 1400 1306 1221 1091
Energy 370 322 281 225
Trajectory 0 -0.4 -5.7
38 Special – 125 grain Velocity 830 776 727 641
Energy 191 167 147 114
Trajectory 0 -2.7 -21.1

In context, the 327 Federal is a flat shooting cartridge that can hit harder at 100 yards then the venerable 38 Special can muster at the muzzle of a barrel. The 327 Federal produces 25% more velocity than the 32 H&R Magnum and, therefore, 50% greater kinetic energy.


Pictured, left – right, GP100 327 Magnum, GP100 357 Magnum and SP101 327 Magnum. The GP100 327 Magnum is built on Ruger’s medium revolver frame, as opposed to the early SP101 327 Magnum that is built on Ruger’s small revolver frame. Buyers of the GP100 version get a more stout frame, an extra round for a total of seven and a longer barrel that generates some pretty impressive external ballistics. For the sake of comparison:

Ruger Model Comparison GP100 & SP101

Model 1748 1705 5759
Caliber 327 Magnum 357 Magnum 327 Magnum
Action Double – Single Double – Single Double – Single
Capacity 7 6 6
Material Stainless Steel Stainless Steel Stainless Steel
Barrel Length (0.00″) 4.20 4.20 3.06
Sight Radius (0.00″) 5.65 5.33** 4.60
Overall Length (0.00″) 9.50 9.50 8.00
Overall Height (0.00″) 6.25 6.25 5.00
Weight* (ounces) 40 39 28
Number of Cylinder Locks 3 3 3
Cylinder Diameter (0.000″) 1.543 1.557 1.360
Cylinder Length (0.000″) 1.615 1.610 1.581
Cylinder Wall Thickness (0.000″) 0.082 0.105 0.084
Cylinder Chamber (0.000″) 0.342 0.382 0.342
Cylinder Throat (0.000″) 0.315 0.357 0.315
Trigger Pull – Double/Single Action 11lbs 4oz/ 4lbs 5oz 6lbs 14oz/3lbs 4oz*** 10lbs 9oz/5lbs2oz
MSRP $701 $701 $607
RealGuns  – Typical $516 $551 $465

*Actual **Williams Fire Sights ***Trigger Worked

The differences between the medium frame GP100 and small frame SP101 versions chambered for the 327 Federal Magnum show up in a number of ways. As an example, the top strap of the SP101 is 0.196″ at the thinnest point, where the GP100 measures 0.268″. The SP101 frame width at the barrel measures 0.736″ the GP100 measures 0.847″. These are just two different types of firearms, one leaning toward robust strength and maximum cartridge performance. The other, similar power in a significantly lighter weight and more concealable form.

The cylinder is secured at three points when closed and ready to fire. Gap between cylinder and barrel began and ended the shooting session at 0.005″ for both guns, which is 0.001″ larger than the gap on my GP100 357 Magnum with a little bit of soot on the face of the cylinder.

The performance difference

Folks who would dismiss the 327 Federal Magnum, placing it in the company of earlier 0.312″ cartridges, might be in for a bit of a surprise. Pictured next to the larger .357 Magnum, the little 327 mag has a pretty good bark and bite. The SP101 greets the shooter with a slap in the hand that suggests there is power in this compact package. The GP100 reduced recoil a bit, but not enough to turn shooting the 327 Federal Magnum into a snooze fest… I believe that’s the celebration right after Oktoberfest.

Cartridge 327 Federal Magnum 32 H&R Magnum 32 S&W Long
COL (0.000″) 1.457 1.350 1.280
Case length (0.000″) 1.200 1.067 0.915
Capacity (Grains) 19.0 16.2 14.8
Max PSI 33,359 23,496 14.,504

Federal ammo rated at 1,400 fps generated 1,389 fps of muzzle velocity when fired from the 3″ barrel SP101, 1,459 fps from the 4″ GP100. Both guns are easy to shoot. The sights are fully adjustable on both, but the GP 100 sights are a bit more beefy and the front ramp is fully serrated to remove all traces of glare. At 50 feet my wife and I both did better with the steadying weight of the GP. She shot a three shot 1 3/4″ group with the GP to my… 1 3/4″ GP group. Then Diane shot a 2 1/2″ group to my 3″ group. Surely the gun in a rest or shooting fixture was capable of much better, but for 50 feet and shooting revolvers, we felt the guns were intuitive in handling. The GP100 version has a consistent and repeatable advantage over the smaller gun.

So far, so good…

So far, my impression of the GP100 is favorable. The heft and extra barrel length produce for significant ballistic gains over the lightweight and compact SP101 and it makes the gun a whole lot easier to shoot accurately.

The GP100 in 327 Federal Magnum is as sturdy as the .357 Magnum version. It feels good right out of the box, but there are lots of spring and sight kits to finesse the gun further if so desired.

The GP100, like the SP101 chambered for the 327 Federal Magnum can also shoot 32 H&R Magnum and 32 S&W Long ammo in a pinch, however, the real performer is the 327 Magnum.

From a handloading perspective, there are no dedicated die sets as sets made for the 32 H&R Magnum and 32 S&W Long can also be set up to load the 327 Federal Magnum. There are lots of components available to optimize for any given application and that is where we are going to pause. Part II will address handloading the 327 Federal Magnum and handload performance.

Ruger’s Seven Shot GP100 327 Federal Magnum Part I
Ruger’s Seven Shot GP100 327 Federal Magnum Part II