Chamber Lengths: It is important to determine the exact chamber length of your gun. Do not try to make a guess based on measuring the chamber with a ruler, etc. The correct way to measure a chamber’s length is with a go/no-go gauge. All original European and British guns had a chamber length (12ga.) of 65mm which is 2 9/16”. These are commonly called 2 1/2” chambers. Early American breech loaders had a chamber length of 2 5/8”. Now, modern guns usually have 2 3/4” or longer chambers. You must have your shell’s length match your gun’s chamber. If it is too long, the shell will not be able to fully open and cause a constriction at the forcing cone. This can be a dangerous situation because pressures and recoil increase which could lead to damage of the gun and shooter. Also, if you own an old original gun with short chambers, do not try to lengthen them, as doing so will take the gun out of proof until it is reproofed with the longer chambers. It is against the law everywhere but the U.S. to take a gun out of proof without reproofing. It also decreases the value of the gun. Make the shells fit the gun, not the gun fit the shells.
Loading Black Powder Shot Shells: There are three types of shell construction available today; paper, plastic, and brass. Let’s address the properties of each.
Paper; The only American made paper shell made is Federal. These are sold as 2 3/4” target loads and are loaded with smokeless powder. NEVER shoot these in antique guns of any kind. Fire them thru a modern, steel barreled, 2 3/4” chambered gun proofed for American pressures. Once fired, you can load them with black powder. Prime with a standard 209 shotgun primer, then charge with the appropriate charge of black powder. Insert the 1/8” nitro card on top of the powder. These can be rammed with plenty of pressure, as black powder likes wad pressure for consistent results. Insert a fiber cushion wad and ram it down on top of the nitro card. You may need to trim the thickness of this wad to obtain proper column height for the crimp. The shot charge is dropped next, then an overshot card is inserted if you are roll crimping. If you are using a star crimp, the overshot is not necessary. If needed for short chambers, shells can be trimmed to a shorter length using a knife or razor blade type trimmer available from Ballistic Products. Plastic; There are many brands of these in two basic types; straight wall and compression formed one piece which have a tapered wall; i.e., the interior diameter decreases from top to bottom. Black powder burns at a higher temperature than smokeless powder, so a plastic shell will not take many firings until the powder melts holes thru the shell itself. I will say, we have been having good longevity out of the new AA’s and STS hulls. Winchester has changed the plastic used in these hulls, and they don’t burn through as fast as the old style. Obviously, the reloading sequence for plastic shells is the same as paper. Although one note. The higher quality plastic shells, such as the old style Winchester AA and Remington STS are of the tapered wall variety and a 12ga. nitro card going down a 12ga. tapered shell will leave a slight bulge visible on the outside of the case when it is seated on the powder. This will not hurt anything and we never had any not go into the chamber. The bulge disappears as soon as you pull the trigger. Some cowboy action shooters are concerned about quick extraction and reloading, and use a 13ga nitro card instead. I do not recommend this because you introduce gas leakage problems.
Brass; To further confuse the issue, there are two types of brass shells made, lathe turned brass, and extruded brass. All of the old original brass made years ago and the new extruded brass marketed by Magtech are extruded from brass slugs and have thinner walls than paper or plastic. Therefore, to seal an extruded (thinwall) brass shell, refer to our wad sizing chart for appropriate wad sizes.
Thin wall brass shells are primed in a variety of ways. Some use Berdan primers, and some use large pistol primers. Rocky Mountain Cartridge manufactures complete loading kits for all sizes of MagTech brass shells to aid in priming and reloading of these hulls. 4D and RCBS make shell holders for 12ga., 16ga., and 20ga. MagTech brass. Huntington’s carry the RCBS shell holders. Buffalo Arms Co. carry the 4D brand. These can be used to prime the shells using a hand primer or loading press. Loading steps for these shells after repriming is the same as the other styles with the exception that you need to use oversized wads. Also, you do not crimp these hulls, and therefore need an overshot card. The overshot will need to be glued in place and we recommend using Duco cement, paraffin, waterglass, etc. to hold the card in place. Another glue worthy of use is arrow fletching cement, such as Fletch-Tite brand. It is made to stick to non porous surfaces and dries quickly. I recommend using one size larger overshot card in extruded brass. For example, in a 12ga. thinwall shell, use 11ga nitro and fiber wads, and use a 10 ga. overshot that is glued in place. This will help insure that your load column is not going to move. Some advantages of a brass shell is that since you don’t crimp them shut, they will last a long time. The depth of the overshot card below the case of the mouth is not important. One mistake that we often hear is filling the case by using multiple cushion wads. This puts unnecessary mass behind the shot charge, and a poor pattern is often the result. This leaves us with lathe turned brass. These shells were originally made by Ballard Rifle & Cartridge Co. and sold to Rocky Mountain Cartridge. These shells have a thicker wall and the interior diameter matches the gauge size, so for example, a 12ga. lathe turned brass shell will use 12ga. wads the same as paper and plastic. These shells also use a glued in place overshot card.
Use of Reloading Machines with Black Powder: There are lots of jobs that can be done with a reloader to increase consistency and cut down on time spent reloading black powder in plastic/paper hulls. Probably the handiest machine is the MEC 600 Jr. Since it is a single stage unit, it can be used for specific tacks such as depriming/repriming, ramming wads, dropping shot, and crimping. I do not charge my shells with black powder using the MEC loader due to concerns with static. I hand charge each one out of a covered container. I usually seat the nitro wad on black powder at 30 lbs. on the MEC scale. We now load both 2-3/4” and 2-1/2” shells with the same machine with out modifications to the press. First, I replaced my factory crimp starter with an all brass starter from Ballistic Products. This starter will restart a crimp on a hull that has been trimmed to 2-1/2” real slick. I then move my final crimp die down as far as it will go, without falling out of the machine, and go to town. Just move it back up to load 2-3/4” shells.
Other Thoughts and Tips: Any kind of primer will work with black powder, although there are two schools of thoughts on this; First, many think that the milder the primer, the better. The thinking is that a mild primers does not seem to over-ignite the powder and bake the fouling that is left in the barrel, thus effecting accuracy/patterns and effecting the performance of a lubed cushion wad. The second is to use the hottest primer available, such as Federal and Winchester magnum primers. The idea here is that the hotter primer burns more of the solids out of the fouling and therefore reduces fouling in the barrel.
When using a MEC machine to load lubed cushion wads into shotshells, place an overshot card on top of a lubed wad before ramming. This does two things. It keeps the lube from building up in the drop tube, and more importantly, it acts as a release for the shot charge. It is important that the shot does not “stick” to the lubed cushion wad when it exits the barrel.
Also, wad sizing in large bore shotgun hulls, especially hulls marked 4 gauge can be confusing... “Cartridges of the World, 8th Edition” says it well...“In most instances, gauges larger that 8ga. were somewhat mis-named. 2ga. shells are actually 4 ga. and 4 ga. shells are actually 5 or 6 ga.”... If you are loading shells of this size, be careful to measure the I.D. of the hull and compare to the sizing chart before ordering wads.