Compared: The .327 Federal Magnum and .38 Special +P

By Chuck Hawks

The .38 Special is one of the most popular, versatile and useful of handgun cartridges. (It is, naturally, covered on the Handgun Cartridges page.) It was introduced in 1902 and has become a worldwide cartridge. Ammunition is available everywhere handguns are legal and there are many models of .38 Special revolvers available, both new and used. The .38 Special has been offered in practically all handguns, past and present, that can handle it. In addition, all .357 Magnum revolvers can shoot .38 Special ammunition. (The .357 Magnum is based on a .38 Special case lengthened by 0.135".) Like almost all revolver cartridges called ".38," the .38 Special actually uses .357" diameter bullets.

In medium size revolvers with 4" or longer barrels, recoil is seldom a problem. The fact that .38 Special revolvers can be built on small, medium, or large frames means that there is a .38 to fit every hand. Except in ultra-light snubby revolvers, where recoil can become a problem, most shooters consider the .38 Special one of the most pleasant personal defense cartridges to shoot.

Over the years, the .38 Special has been loaded to several different power levels, from very mild target loads to High Velocity loads intended for use only in large frame revolvers; the latter were the predecessor of the .357 Magnum. The current SAAMI mean maximum pressure limit for the standard .38 Spec. is 17,000 psi. Typical factory loads, measured in a 4" vented barrel, give the standard pressure 125 grain jacketed bullet a muzzle velocity (MV) of 850 fps and 201 ft. lbs. of muzzle energy (ME). The SAAMI pressure limit for .38 Spec. +P loads is 20,000 psi. At this pressure, the .38 Spec. will drive a 125 grain jacketed bullet at a muzzle velocity (MV) of 945 fps (Winchester figures).

In one shot stopping power, the .38 Special is about the equal of the .380 ACP when fired from a snub-nose revolver with a 2" barrel. From a 4" revolver using +P ammunition, the top .38 Special load scores a respectable 83% one shot stops, based on actual shooting results compiled by Marshall and Sanow.

The .327 Magnum (also covered on the Handgun Cartridges page) was introduced by Federal Cartridge in 2008. It is the latest in a long line of .32 caliber revolver cartridges based on cases with identical rim and head dimensions, all of which actually use .312" diameter bullets. The .32 S&W begat the .32 S&W Long, which begat the .32 H&R Magnum, which begat the .327 Federal Magnum. Each evolutionary step increased the length of the basic .337" diameter case in order to provide more powder space and consequently higher velocity, energy and stopping power. The .327 Magnum can safely shoot all of these cartridges, as its chamber is the longest of the bunch. Incidentally, since the .32 ACP auto pistol cartridge is a semi-rimmed design that uses the same .337" case diameter as the revolver cartridges, .327 Magnum revolvers can also chamber and fire .32 Auto cartridges. In practice, .32 H&R Mag. and .327 Mag. cartridges will probably provide the best accuracy in the long .327 chamber.

The original .32 S&W qualifies as a "mouse gun" cartridge (98 grain LRN at 705 fps / 115 ft. lbs.) and was often offered in pocket revolvers. The .32 S&W Long (also called the .32 Colt New Police) offers modestly improved performance (98 grain lead bullet at 780 fps / 130 ft. lbs.) and was adopted by a number of police departments in an earlier and more innocent age. The .32 H&R Magnum (85 grain JHP at 1120 fps and 235 ft. lbs. from a 5" barrel) was designed to achieve .38 Special energy and, hopefully, stopping power in a flatter trajectory, .32 caliber format. Like standard velocity .38 Special combat loads, its recoil and muzzle blast are moderate. The .32 H&R Mag. performs well in small frame revolvers with 3" barrels.

The .327 Federal Magnum, however, is a horse of a different color. The .327 Magnum cartridge looks like a slender .38 Special +P, as it is about the same overall length. It was, in fact, designed to be chambered in revolvers with .38 Special length cylinders. Factory loads from the ATK Sporting division, which includes Federal, Speer, Fusion, Blazer and other brands, are offered with 85, 100 and 115 grain bullets. The .327 is not a moderate cartridge when fired from small frame, short barreled revolvers. It sounds and kicks like the true magnum cartridge it is.

Full power factory loads from Federal and Speer, using a 100 grain bullet at 1500 fps and 500 ft. lbs. from a 4" barrel, achieve higher muzzle velocity and flatter trajectory than the .357 Magnum, .41 Magnum and .44 Magnum. The energy exceeds that of the 9mm Luger, .40 S&W, .45 ACP and 45 Long Colt from the muzzle to at least 75 yards. In terms of velocity, energy and trajectory, the .327 Magnum is closer to the .357 Magnum than any of the other handgun cartridges I just mentioned.

The first revolver chambered for the .327 was the Ruger SP101, which is supplied with a 3" barrel. This is a strong, small frame revolver. It can safely handle the .327 Magnum's pressure, but the 3" barrel is insufficient to deliver the cartridge's full performance, the muzzle blast is excessive and the recoil is sharp and unpleasant. It is a bad combination. Even the Federal Personal Defense Low Recoil load, which is still a hot load, is too much for the SP101. If your choice for home or personal defense is a Ruger SP101, stick with .32 H&R Magnum ammunition. (Our review of the .327 Ruger SP101 can be found on the Product Reviews page.)

A far more suitable platform for the .327 Mag. is the Ruger Blackhawk. This medium frame (.41 caliber size) revolver is supplied with a 5.5" barrel and, in .327, an eight shot cylinder. It has a hand filling grip and the heft to tame the .327's recoil, with enough barrel length to achieve the advertised velocity. Of course, the Blackhawk is also available in .357 Magnum/.38 Special caliber, so Blackhawk revolvers are ideal for both the .38 Special +P and .327 Magnum cartridges. (Our reviews of .327 and .357/38 Blackhawks can be found on the Product Reviews page.)

The Comparison

We will compare the .327 Federal Magnum and the .38 Special +P in velocity, kinetic energy, trajectory, sectional density, bullet cross-sectional area and recoil. Federal Cartridge offers factory loaded ammunition for both cartridges, so we will use Federal loads for comparison.

To represent the .327 Magnum we will use two Federal loads. The Premium Personal Defense Low Recoil load is loaded with an 85 grain Hydra-Shok (H-S) JHP bullet at less than maximum velocity. Full power.327 Magnum ammunition will be represented by the relatively economical American Eagle 100 grain JSP load.

The whole point to +P ammunition is to maximize .38 Special performance, so there is no low recoil .38 +P load. The.38 Special +P will be represented by the full power Federal Premium Personal Defense load using a 129 grain Hydra-Shok JHP bullet.

These are reasonable self defense and field loads for their respective calibers. Federal ballistics for both calibers are taken in 4" vented test barrels that simulate typical revolver barrels and we will use their figures in this comparison.


Velocity is important for initiating bullet expansion and it is the most important factor in calculating kinetic energy. Higher velocity flattens trajectory, making hitting easier at extended ranges and particularly at unknown ranges in the field. Here are the velocities in feet per second (fps) of our comparison loads at the muzzle, 50 yards and 100 yards.

  • .327 Mag, 85 gr. H-S: MV 1400 fps, 1220 fps at 50 yards, 1090 at 100 yards.
  • .327 Mag, 100 gr. JSP: MV 1500 fps, 1320 fps at 50 yards, 1180 fps at 100 yards.
  • .38 Spec, 129 gr. H-S: MV 950 fps, 900 fps at 50 yards, 870 fps at 100 yards.

As you can see, there is really no comparison in terms of velocity. The .327 is much faster at all ranges. In fact, the .327 loads are 140-230 fps faster at 100 yards than the .38 Spec. +P is at the muzzle. This bodes well for the .327 in terms of energy, flatter trajectory and bullet expansion downrange.


Kinetic energy is defined as the ability to do work. In this case, the "work" involved is primarily powering bullet penetration and expansion. Both are, of course, necessary for lethality. Here are the energy figures in foot-pounds (ft. lbs.) for our comparison loads at the muzzle (ME), 50 yards and 100 yards.

  • .327 Mag, 85 gr. H-S: ME 370 ft. lbs., 280 ft. lbs. at 50 yards, 225 ft. lbs. at 100 yards.
  • .327 Mag, 100 gr. JSP: ME 500 ft. lbs., 390 ft. lbs. at 50 yards, 310 ft. lbs. at 100 yards.
  • .38 Spec, 129 gr. H-S: ME 260 ft. lbs., 235 ft. lbs. at 50 yards, 215 ft. lbs. at 100 yards.

Comparing the two personal protection loads, the .327 has a 110 ft. lb. energy advantage at the muzzle. At 100 yards, this has decreased to an insignificant 10 ft. lbs. This is because the relatively blunt pistol bullets shed velocity rapidly and the faster a bullet goes the more air drag it creates and the faster it slows down. However, the .327 personal protection load still wins the energy comparison from the muzzle to 100 yards. The full power .327 Magnum field load is in a class by itself, clearly out performing both personal protection loads at all distances.


It should be remembered that, in the field, game is not shot right off the muzzle, so a relatively flat trajectory is important to small game and small predator handgun hunters. Both the .327 Magnum and .38 Special +P are suitable for such use. For those who carry a handgun for protection against two-legged predators when camping, fishing or hiking, there is the possibility of having to defend oneself against an aggressor armed with a rifle and in that situation a flat trajectory that allows you to reach well beyond normal urban self-defense ranges is crucial.

For field use, I would suggest a 100 yard zero for the .327, which would mean a mid-range trajectory (maximum bullet rise) of only 2.5-3 inches (depending on the specific load) between the muzzle and 100 yards. This will give a useful range of about 125 yards before holding over becomes necessary on human size targets. At 150 yards, the 100 grain .32 bullet should hit about 8" below the point of aim.

Zero our .38 Special +P load at 100 yards and the mid-range trajectory (MRT) will be around 5" and the drop at 150 yards about 17". To keep the MRT similar to that of the .327 at 50 yards (about 2.5"), zero the .38 +P at 75 yards, in which case the bullet will hit about 5" low at 100 yards, which is still acceptable for field use. At 150 yards, the .38 +P bullet will be a couple of feet low.

Federal Cartridge bases their handgun trajectory information on a 25 yard zero. This is fine for a home defense handgun, but it does not take advantage of the maximum point blank range potential of the .38 Special +P or .327 Magnum cartridges if they are to be used in the field. For comparison with the two paragraphs above, here are the Federal trajectory figures (in inches) for our selected cartridges, based on a 25 yard zero from a revolver with iron sights.

  • .327 Mag, 85 gr. H-S: +/- 0" at 25 yards, -0.4" at 50 yards, -2.2" at 75 yards, -5.7" at 100 yards.
  • .327 Mag, 100 gr. JSP: +/- 0" at 25 yards, -0.2" at 50 yards, -1.6" at 75 yards, -4.5" at 100 yards.
  • .38 Spec, 129 gr. H-S: +/- 0" at 25 yards, -1.6" at 50 yards, -5.9" at 75 yards, -13.0" at 100 yards.

Those trajectory figures clearly illustrate the advantage of a 75 to 100 yard zero for use in the field. However, the high velocity of the .327 means that, even with a 25 yard zero, it is still a useful field cartridge, at least out to 100 yards. However, zero a .38 +P at 25 yards and the drop at 100 yards becomes unacceptable.

Sectional Density (SD)

Sectional Density is the ratio of a bullet's weight (in pounds) to its diameter squared (in inches). SD is important when comparing cartridges and loads because, other factors (such as impact velocity and bullet design) being equal, the bullet with the greatest SD will penetrate deeper, creating a longer wound cavity and increasing tissue destruction. Obviously, however, if the bullet penetrates all the way through the target, wounding ceases. Superior SD also improves the penetration of barrier materials, giving the bullet a better chance to reach a target on the other side (other factors being equal).

The actual bullet diameter for the .327 is .312". The actual bullet diameter for the .38 Special is .357" Here are the SD's for our selected bullets.

  • .312", 85 grain = .125 SD
  • .312", 100 grain = .147 SD
  • .357", 125 grain = .144 SD

As you can see, the SD's of the .32/100 grain bullet and .38/129 grain bullet are similar. Either has an advantage over the .32/85 grain bullet. Since the .32/100 grain bullet is a soft point, rather than a faster expanding hollow point, and it has the best SD, we can predict that it will be the deepest penetrator among our comparison loads. Among the heavier bullet weights factory loaded, but not included among our comparison loads, the .32 caliber / 115 grain bullet has a SD of .168 and the .38 caliber /158 grain bullet has a SD of .177.

Cross-Sectional Area

Other things (such as bullet construction and expansion ratio) being equal, a fatter bullet makes a larger hole and consequently a wider wound cavity with increased area. Note that cross-sectional area is independent of bullet weight. Here are the cross-sectional areas of our two calibers.

  • .312" = .0760 sq. in.
  • .357" = .1007 sq. in.

Obviously, the .38 +P (.357" diameter bullet) has an advantage over the .327 (.312" diameter bullet) in cross-sectional area.


Greater recoil is always bad. It makes accurate bullet placement more difficult by increasing flinching and increases the recovery time required between shots. For self defense handgun cartridges, you can definitely have too much power, which is why the .454 Casull and .44 Magnum are not generally recommended for personal protection. Fortunately, neither the .327 nor the .38 +P are in that category. Both deliver sharp recoil in small, one pound (16 ounce) revolvers. However, in revolvers of substantial weight, such as the approximately three pound (48 ounce) Ruger Blackhawk, both calibers become rather docile and are easily controlled by reasonably experienced handgunners. Here are some approximate recoil energy (ft. lbs.) and velocity (fps) figures for our comparison loads fired in a three pound revolver. For comparison, I have added a full power .357 Magnum load.

  • .327 Mag, 85 gr. at 1400 fps: 2.2 ft. lbs.; 6.8 fps
  • .327 Mag, 100 gr. at 1500 fps: 4.3 ft. lbs.; 9.6 fps
  • .38 Spec, 129 gr. at 950 fps: 2.1 ft. lbs.; 6.7 fps
  • .357 Mag, 125 gr. at 1450 fps: 6.3 ft. lbs.; 11.6 fps

From these figures it can be seen that the Personal Protection Hydra-Shok 85 grain .327 and 129 grain .38 +P loads deliver similar recoil levels. Subjectively, it is difficult to tell the difference. However, the full power, 100 grain .327 load develops about twice the recoil energy and about 45% higher recoil velocity than the .38 +P load. In a Ruger Blackhawk it remains a controllable load, but you can easily tell that it kicks harder. In a light weight revolver, this is a punishing load to shoot.

The recoil of the 125 grain .357 Magnum load exceeds even the full power .327 load by a wide margin. It could be concluded that, in terms of recoil, the full power .327 is in-between the .38 +P and the .357 Magnum.

Summary and Conclusion

As you can see from the foregoing, our .327 Magnum comparison loads meet or exceed the performance of our .38 Special +P load in every category, except bullet cross-sectional area. In a Ruger Blackhawk revolver, the .327 even offers two more shots (eight instead of six). It is pretty hard to argue with that. If I were choosing between a Ruger Blackhawk in .327 or .38 Spec. +P for home defense or field use (and I own both), I'd go with the .327 Mag. Its flatter trajectory also makes it a superior predator and small game hunting cartridge.

Both .327 and .38 Special +P revolvers can handle mild, lower power practice loads. This means target and standard velocity ammo in .38 Special and .32 Long and .32 H&R cartridges in the .327 Magnum.

For reloaders, there is a reasonable selection of suitable .32 caliber (.312") bullets. These range in weight from about 60 grains to 115 grains, as supplied by the major bullet makers. The bullet selection in .38 caliber (.357") is more extensive, probably the greatest selection of any handgun caliber. Bullet weights range from about 95 to 200 grains in a great assortment of designs.

The .38's main advantage is in the number of new and used revolvers on the market and the very wide distribution of .38 Special +P ammunition. Greater availability also generally means lower ammunition prices. For the high volume shooter of factory loaded ammunition, the .38 Special is the most economical of centerfire revolver cartridges.

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Copyright 2012 by Chuck Hawks. All rights reserved.