Handloading the .38 Special for Snubnose Revolvers
April 18, 2018
Snubnose revolvers continue to be popular for self-defense. And one of the most popular cartridges- if not the most popular cartridge- for those revolvers is the .38 Special. Plenty of components for handloading are available, so there aren't any concerns there. But handloaders need to know a few peculiarities about building the ammunition for those short-barreled revolvers. One is the need to securely crimp the case mouths to preclude the bullets from jumping the crimp.
Just about everyone reading this magazine is aware of the need to securely crimp the case mouths on ammo for heavy-recoiling magnum handguns, but how many know the same thing is necessary for a relatively lightweight handgun?
Another critical consideration for handloading for a short-barreled revolver is selecting a proper powder-and-bullet recipe. Why? Because we are trying to balance two opposing performance criteria: bullet penetration and expansion.
An FMJ bullet penetrates deeper because it doesn't expand and all of the bullet's energy is expended on penetration. Depending on point of impact, even the fastest FMJ bullet may not immediately disable the bad guy.
On the other hand, a similarly speedy bullet having the thinnest possible jacket with multiple skives surrounding a large hollow cavity in the nose, often filled with a polymer plug to enhance expansion, probably won't penetrate at all and could likely blow up upon impact. Messy, sure, but again, the bullet may not be immediately disabling.
Of course, balancing penetration and expansion is most difficult when handloading ammo for short-barreled handguns.
Even the best personal-defense bullet must be launched at a muzzle velocity that ensures it will impact fast enough to properly expand. In most handguns, the propellant is fully combusted in the first couple of inches of the barrel. However, a longer barrel allows the propellant gas pressure to continue to accelerate the bullet until it exits the muzzle. A snubnose revolver necessarily sacrifices ballistic performance for personal-defense considerations such as concealment and ease of carry.
But there's no need to further curtail cartridge performance by using less-than-optimal components, such as a bullet that's too heavily constructed to expand at expected lower velocities or a propellant that can't transfer the most muzzle energy possible to the bullet in the short barrel.
A Word of Warning
A word of warning is in order. You must take extra care to ensure you do not inadvertently double or triple charge a case. The .38 Special was originally sized for a case full of blackpowder under the bullet. Modern smokeless propellants are much more energetic, so a typical charge of 6.0 or 7.0 grains barely fills a quarter or so of the case volume.
I always throw powder for a tray full of cases and, using a bright light, carefully inspect each one. I usually randomly select and weigh a few just to be sure. Because crimping the case mouth into the bullet is required, I also trim each batch of brass to a uniform length so that when seating the bullets I can apply a firm, uniform crimp.
As readers of Shooting Times know, SAAMI is the federation of arms and munitions manufacturers that establishes the performance and testing specifications for ammunition produced in the United States. One of the technical specifics included for each cartridge is the maximum average pressure (MAP). Originally stated in copper units of pressure (CUP), the MAP for most current cartridges has been updated to pounds per square inch (psi). The .38 Special's MAP is 17,000 psi, whereas for the .38 Special +P it is 20,000 psi. The proof pressure MAP specified by SAAMI is 29,500 psi for both rounds. Therefore, .38 Special +P ammo can be as much as 17.5 percent hotter than standard .38 Special. All newly manufactured .38 Special revolvers must be proof tested to the same higher proof pressure level.
What You Can Expect
As you can see in the accompanying chart, several of the handloads I prepared maximize ballistic performance in a short-barreled S&W Model 637 revolver. In most cases, they feature light-for-caliber bullets constructed to expand at minimum velocities. Light jackets and generous hollowpoints with augmented expansion design features are the norm. I also included a heavy but soft, swaged lead hollowpoint bullet for comparison purposes.
The results were obtained by firing three, five-shot groups at 12 yards from a sandbag rest. Almost every group was centered low and left. The Model 637 features fixed sights, so I can adjust the point of aim to compensate. However, because it's a personal-defense gun intended for up-close shooting, there's really no need to alter the sight picture. Actually, I've learned to simply place the front sight where I want the bullet to hit and squeeze the trigger. I'm confident that if any future situation warrants firing, I'll be ready.