Make Your Own .45 Shotshells
Adding some kapok helps fill space and prevent powder leakage around the cork discs.
I have been experimenting with making shotshells for a 45 ACP. What I’m presenting here is an “almost complete” project. I’ve been standing on the shoulders of giants when it comes to load development, and I’m looking forward to your input on how to improve this load.
Most commercial shotshell loads are for revolvers. Some of the ones for autos are pretty good, but they don’t check all of the boxes for handloaders. First, we like to develop loads to our preferences. Second, what we make has to be reloadable, and the performance has to be repeatable. Third, the shells must function reliably in an auto.
After cutting the .308 brass, it has to be annealed. For pistol brass,
I just heat it until it changes color (about 5 seconds), then let it cool
on its own. It took much longer to get the color change on rifle brass.
Brass
I used cut-down brass from .308 casings. The dimensions of the .308, specifically the commercial version of the 7.62 x 51mm, are very similar to the 45 ACP on the bottom end, including the extractor cut. There are other candidates, but the .308 is the best fit.
I started to cut the brass down using a ceramic cut-off saw, which I occasionally use for pistol brass. After breaking two blades, I chucked the cases into my lathe, where things went smoother.
Lindsey used a Frankford Arsenal Platinum Series Case Trim
and Prep Center to chamfer the inside and outside of the mouth.
This not only helps star the neck, but it also allows for the top “crimp”
of the brass at the end of the reloading cycle.
Lindsey used a pocket lathe to cut the .308 brass down to approximately
the length, then trimmed it to 1.254". The outside diameter of a .308
brass approximates .45 Auto brass, except the walls are much thicker.
Brass Gymnastics
There are a few different ways one can make a handgun-sized shotshell. For .45 caliber, one can use trimmed .410 wads inside a case. This works well for .45 LC shells but doesn’t give enough room for .45 ACP. One can use shotshell capsules (plastic capsules that hold shot) in the shape of bullets. They load in a manner similar to metallic reloading. I picked a third method, “sizing a cartridge into a bottleneck style brass.” To do this, I used three different die sets: a .45 ACP sizing die, a carbide .40/10mm sizing die for the necked-down portion and a .357 SIG sizing die to form the “nose” of the shell.
Changing the size of a case from .45 to .40 requires pretty malleable brass. The brass needs to be annealed, which means heating it and letting it cool. Once I cut it, I used a propane torch to heat the neck until it changed color. For the cut down .308, it took about 10 seconds on each side with a propane torch. After heating, just let the brass cool to room temperature.
I cut the brass a little oversized, then trimmed it evenly using my Frankford Arsenal case prep tool. I wanted the cases to be completely concentric and square before I chamfered the inside and outside of the case mouth.
I put the chamfered brass into a .40/10mm carbide die and used a generous swab of Hornady Unique case lube to prevent collapsing the case. Originally, I used a Sharpie line on the brass to gauge how far to neck it down. I found the best way was to adjust the dies to the upper limit of the press.
I wanted to have the shot column as long as possible, so I cut the brass as long as possible. I cut it to 1.285″ on the lathe. It really turned out to be a rough cut, until I trimmed to 1.280″. Later, when I used the .357 SIG sizing die to create the nose of the shell, I tried to get the OAL as close to 1.254″ as possible. There was a balance between getting all 120 grains of shot in and getting the shell (not cartridge!) to fit in a standard .45 ACP magazine.
With the load assembled, the nose of the shell is guided
into a .357 SIG sizing die. The part forms the shoulder of
the .357 SIG.
The Fill
I used Winchester Large Pistol Primers and started with 5.5 grains of 231. I then added a thin pinch of kapok to the powder, tamping it down with a dowel. This prevents the powder from slipping past the cork disc we’ll add next.
I bought a 1/8″ thick roll of cork from Hobby Lobby and used a cardboard punch to make 10.5mm circles. This kind of punch is available as a leather hollow punch in craft stores.
I put one cork disc over the kapok, then weighed and loaded the shot using a powder funnel. I put another cork disc over the shot, then used the .357 SIG sizing die as a “crimping tool” to form a bullet shaped nose over the shell. This was enough to hold the cork disc over the payload. If I were going to store the shell for future use, I would seal the top with hot glue.
The fired case expands to try and fill the chamber, just like a normal cartridge.
Performance
The necked-down shell will barely hold a compressed load of 120 grains of #6 shot. I found that the penetration was awesome with #6. Number 9 shot is denser and may fit better in the shell, but #6 tore up the targets with authority.
I weighed the #6 shot, and it averaged 1.5–1.7 grains each. The 120 grains averaged 64 pellets in each payload. At ranges closer than 7 yards, I could keep the spread under 25″.
Recoil was lighter than standard pressure 9mm. I did not experience any barrel leading, nor was there any inconsistency in behavior from one shell to another. They cycled the gun normally, although I found 5.5 grains of 231 was a little too light in my 1911; 5.7 grains worked better.
The brass takes on the dimensions of the chamber, just as any metallic cartridge would. The nose straightens out, and the shoulder becomes less abrupt. I have not loaded any cases twice, but I’m guessing the .40/10mm section will need to be resized eventually.
Utility
This is not a self-defense load but rather one useful for rats and snakes inside about 7 yards. I would be delighted to hear how you might take this design and run with it.
