Handloading Brass Shotshells Pt. 3
Date: Apr 04 2014
In developing the load data for Part III, a different chronographing protocol was established and it was discovered there needed to be some clarification of Part I and Part II. To begin with, it was subsequently learned that the original CBC brass shotshell primer, the 6.45mm (#56 Tupan), was a Berdan primer and when the decision was made to offer a Boxer-primed version, the shells were cut for a large pistol primer. There were never any made for small pistol primers despite some earlier claims that appeared in print.
Also, earlier I noted that MAGTECH was importing 12-, 16-, 20- and 28-gauge shells along with the .410 bore. This must be expanded to include 24-gauge shells and I have samples of each on hand. All of the gauges are nominally 2½inches in length but as noted may differ slightly. The .410 shells, on the other hand, while listed and labeled on MAGTECH boxes as 2½inches are actually shorter, much closer to 2¼inches. A random sampling of those on hand ran from 2.308 to 2.330 inches.
In Part II, I noted that all published velocities were recorded at a distance of six feet from the muzzle to the mid-point of the chronograph start/stop screens. Upon review of my data I must state that this is incorrect. Some, perhaps most, of the data were recorded at three feet, or so. However, difficulties can occur when attempting to record shotshell velocities at this distance so, after consultation with Dr. Ken Oehler, of Oehler Research, Inc., the following protocol was established and used for all the data that appear in Part III:
a) the distance from the muzzle to the mid-point of the start/stop screens was carefully kept at six feet.
b) because black powder was being used, the screens were protected with a clear covering such as strips from a plastic sandwich bag and replaced to begin each chronographing session.
c) because so many of the velocities are subsonic, a baffle was placed two feet from the muzzle to deflect gases from triggering the start screen before the shot charge arrived. The result was a system of muzzle, a baffle at two feet, start screen at four feet, mid-point at six feet and stop screen at eight feet.
In spite of these efforts, it is possible that errant gases did occasionally trigger the start screens resulting in abnormally low velocities. To preclude that from happening, whenever the velocities of a shot string were not reasonably consistent, the entire string was shot again.
In preparing for this expansion of load data I had a choice of a half dozen black powders plus a couple of replica powders. To reduce the choices to something less than a life’s work, I loaded all of the powders to a standard 12-gauge, three dram, 11/8ounces of shot recipe and compared them. This is what I got:
GOEX FFg 948 fps
GOEX Express 940 fps
GOEX Cartridge 844 fps
Schuetzen FFg 884 fps
Swiss 11/2Fg 872 fps
KIK FFg 931 fps
Pyrodex RS 932 fps
Triple Se7en 1079 fps
Reviewing the results, I concluded there was no real distinction to be made and I elected to restrict my black powder use to GOEX FFg. I must state that while the Swiss 11/2Fg with its larger and slower-burning granules and the GOEX Cartridge are not ideal for this application, any of the others could be substituted for the GOEX FFg in the load data without concern. I was particularly impressed with the KIK powder. It burned relatively cleanly and produced small extreme spreads. As some may recall, it was once imported by GOEX for a short while. It is made in Slovenia and is now available from Western Powders of Miles City, Montana. Pyrodex RS was chosen as a replica powder as it is our most popular replacement for black.
Hodgdon’s Triple Se7en requires some explanation. Hodgdon recommends that it be substituted for FFg black powder at a 85% level by volume. This means that if one’s FFg charge was 100 grains, for example, the powder measure should be set 85 grains and that much Triple Se7en dispensed for equal performance. This proved to work for brass shotshell loading as well and it was found the 85% substitution level closely mimicked the performance of GOEX FFg. A 100% volume-for-volume substitution produced much higher velocities as shown on page 21.
Now to the load data. At the beginning of each gauge section are the constants: gauge, shell, primer and wad column. On each data line are the variables. Following is a description of each.
In the black powder era, shotshell powder charges were measured in drams. A dram equals 1/16 of an ounce or 27.34 grains. A 12-gauge shell, or box of shells, labeled 3-11/8-6" told the shotgunner the contents contained three drams of powder and 11/8ounces of number six shot. A knowledge of dram tables would also tell the shotgunner that the nominal velocity of this load was 1200 fps. Few made the connection, relying on the knowledge that 3¾-1¼-4" was a good duck load, 2¾-1-8" was a good quail load, etc. As smokeless powder replaced black, the system was carried over to reflect that a particular smokeless powder load was the equivalent of its black powder predecessor. Thus a 12-gauge, 3-11/8-7½" label meant that sufficient smokeless powder was used to push 11/8ounces of number 7½shot to the same velocity as three drams of black powder. By relying on dram equivalent tables for each gauge for these data, it was easy to determine which practical and historic combinations were available to us and likely to be of interest.
The weight of the shot charge in ounces used in the load. The actual pellet size to be determined by the target or quarry.