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Performance of Revolver Handgun Using Shotgun Ammunition

Alan Cross November 20, 2012

Law enforcement officers carry handguns in their day-to-day activities, and those handguns are selected on the basis of manufacturers’ performance data and personal shooting experience. Additionally, the weapons must be proved adequate for offensive and defensive use in almost any situation involving armed criminals.

Choosing an effective weapon often requires examining a wide variety of what appear to be the outstanding capabilities of the weapon of choice. Thus, that weapon must have reliability, accuracy, a rapid firing capability, a large magazine capacity, and excellent penetration capability and stopping power. Many of these data are available from the manufacturers, but experience and observation of performance on the range also play an important role. The choices made are usually revolvers or semiautomatic handguns that fire that have a single propellant charge, a single bullet, and a magazine of variable capacity.

However, a revolver has become available that has a magazine capacity of six .410-bore shotgun shells, each with a single propellant charge and four 0.361-inch-diameter spherical in-line lead projectiles. This type of handgun has a much greater probability of hitting its target than does a conventional handgun firing conventional single-bullet ammunition because of the multiple rather than single projectiles discharged from the muzzle each time it is fired. The velocity of the multiplicity of shot discharged from the .410 handgun is 1200 feet per second (FPS), which may be somewhat greater than the velocity of the shots from most but not all handguns that fire conventional single-bullet ammunition. As a result, the combination of higher velocity and lower weight of the individual projectiles of the .410 ammunition compensates for the heavier weight and lower velocity of the heavier-weight bullets used in conventional handguns. Therefore, the penetration capabilities of the .410 are about the same as those of conventional handguns that fire single-bullet ammunition. This characteristic is particularly important in situations in which the target is shielded by glass or metal enclosures or when other obstacles have to be penetrated before the target can be reached.

However, other characteristics of importance also must be considered. Among these,
accuracy may be the most important. Although the number of hits made with each firing of the .410 may be greater when the targets are close to the shooter, this may not be the case with more remote targets, which can be hit with greater accuracy with conventional handguns and ammunition. The .410 shotgun shell revolver is at a disadvantage in these situations.

Target Shot Distribution Data

Shot distribution data for various shooter-to-target distances for the.410-bore shotgun shell revolver are given in Table 1.

Table 1: .410 Bore Shotgun Shell Revolver Shot Distribution Data

Calculated Shot Grouping Data

A measure for weapon accuracy and the proficiency of a shooter is twofold. First, the shots fired must be close to the aiming point, and second, the placement of multiple shots must lie within a circle, centered at the aiming point, that has as small a diameter as possible, preferably no more than 3 inches. This is possible for the .410 shot shell revolver even if the shooter is an inexperienced one, but only when the target is reasonably close to the shooter – say, about 15 feet – but is entirely possible at much greater ranges – say, about 75 feet – for an experienced shooter using a conventional .45 semiautomatic handgun that fires conventional ammunition.

Although Figure 1 provides the observed shot grouping diameter for only a single .410 round, it was of interest that the shot grouping for this round corresponded reasonably well with the calculated shot groupings at various shooter-to-target distances, as indicated by the curve in that figure, which was generated from Equations 1 through 5. The pertinent variables needed to estimate the shot groupings are as shown in the definitions of terms for Equations 1 through 5. The muzzle velocity is dependent on propellant weight, projectile weight, barrel length, barrel diameter, and muzzle velocity. The variables indicated and the relationships between variables are discussed at length elsewhere.1 However, the muzzle velocity of the shot shells is already known from data obtainable from the manufacturer, so that the calculations referred to are unnecessary at this time and shot grouping diameters can be calculated from Equations 1 through 5:

Figure 1 and 2: (top) Shot grouping diameter for a .410 round. (bottom) Four-shot cluster for a shot shell cartridge

It has been assumed in Equations 1 through 5 that despite the fact that the shots in the shot shell cartridge are arranged in a row of four, the shots leave the muzzle as a four-shot cluster, as shown in Figure 2. As a result, the surrounding air passes horizontally and vertically through the cluster as shown, causing the shot to be displaced vertically and horizontally as a result of the passage of air through the spaces between the shots in the cluster at a velocity equal to the velocity of the shot:

  • (Re) = Reynolds number, unitless
  • (Dshot) = shot diameter, feet
  • (Vair) = air velocity in spaces in .410 shot cluster, feet/second
  • (Dens. air) = air density, pounds/cubic foot
  • (Visc. air) = viscosity of air, pounds/foot second
  • (Shot drag) = air drag on shot, pounds
  • (Cd) = drag coefficient2, unitless
  • (Acc.shot) = shot acceleration caused by air drag, feet/second2
  • (D) shot grouping = diameter enclosing shots on target, feet
  • (L target) = distance of target from shooter, feet
  • (t) = travel time from shooter to target, seconds

Steel Plate Penetration Calculations

Equations 6 through 8indicate the steel plate penetration capability of the individual 70-grain shot pellets fired from the .410 shotgun shell revolver so that they can be compared with that of the single 230-grain bullet fired from a conventional .45 semiautomatic handgun. The penetration data do not account for the effects of bullet or shot deformation, although the latter could reduce the calculated penetrations significantly.

Where:

  • (Fshot) = impact force on steel plate, pounds
  • (Wshot) = shot weight, pounds
  • (Acc.)shot = shot deacceleration resulting from impact force (F), feet/second2
  • (g) = acceleration of gravity = feet/second2
  • (Vshot) = shot velocity at impact = feet/second
  • (Lplate) = thickness of steel plate, feet
  • (Dprojectile) = projectile diameter before impact, inches
  • (Sshear) = shear stress3 for annealed steel plate with 0.2 % carbon

 

Performance Data and Conclusions

Comparative performance data for a shot shell revolver and a conventional .45 semiautomatic handgun are given in Table 2, and targets for both are shown in Figures 3 and 4.

Table 2: Comparative Handgun Data

 

Figure 3: Target cluster for a .410 shot shell revolver

Figure 4: Target cluster for a .45 semiautomatic

Conclusions

 

Although the shot shell revolver provides a means of assuring the infliction of serious multiple damage to a target at close range – say, 10 to 20 feet – when used by an inexperienced shooter, the severity of the damage would be minimal compared with that attainable by an experienced shooter firing a weapon such as a .45 semiautomatic even at much greater ranges of 75 feet or more. Therefore, the .45 or a comparable weapon would be the carry weapon of choice for an experienced shooter and the .410 shotgun shell revolver would be the carry weapon of choice for an inexperienced shooter.

Notes

  1. Cross, Alan. Removal of Fouling Deposits on Heat Transfer Surfaces in Coal Fired Process Heaters and Boilers. Chemical Engineering, vol. 116, no. 7, p. 44, 2009.
  2. Binder, R. C. Fluid Mechanics, 2nd ed. Englewood Cliffs, NJ: Prentice-Hall, 1956, p. 173.
  3. Marks’ Standard Handbook for Mechanical Engineers, 10th ed. New York: McGraw-Hill, 1978, pp. 13–15.
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