Making and shooting Enfield-style cartridges has been, for me, an ordeal of trial-and-error that took several years, and a great deal of frustration, to re-discover what works effectively. I say "re-discover" because all of this was decisively figured out in the 1850s (see my article on the history of the Enfield cartridge for a more thorough handling of this subject).
Many Enfield shooters, attempting to make historical ammunition, give up in frustrated exasperation because their cartridges don't work, for one reason or another. To hopefully spare current and future Enfield shooters from the same exasperations, here are ten "rules" for making Enfield cartridges that, if followed, will result in ammunition that performs much better. I have resisted the temptation to begin each rule with "Thou shalt."
1. Use dead soft pure lead. This is important if you are shooting the .568-caliber bullet, and it is absolutely indispensable if you are shooting the .550-caliber bullet. These bullets must expand a great deal, and pure soft lead expands best. Harder alloys, by definition, are not conducive to expansion. Your lead should be no harder than a 7 on the Brinell scale, and preferably even softer than that. Historically, the Royal Laboratory at Woolwich tested every batch of lead for purity, and if tin, antimony, or other contaminants were detected, the entire lot was rejected.
2. Make well-cast "perfect" bullets. Perhaps someday we will find a philanthropist who will build a bullet-making machine that forms flawless, perfect bullets, like the historical British bullets that were produced in dies under high pressure. Until then, we are forced to settle for cast bullets, with all their associated imperfections. Make sure your bullets are cast well, without cavities or severe wrinkles or other deformities. The sides of the Pritchett style bullet should be smooth; wrinkles and other flaws can provide a textured surface that the cartridge paper can be forced to cling to under the intense pressure of firing. There should be no voids or air bubbles in the bullets, which can affect their accuracy in flight.
3. Use hard expanding plug. This is most important for the .550-caliber bullet; the .568-caliber bullet benefits immensely from an expanding plug but can achieve accurate shooting without one (the original Pritchett bullet did not use a plug, and was quite accurate in "target range" conditions). I recommend a plug made from a hard, light substance for both calibers. Milliput and Bondo make very effective plugs. Oven-cured polyclay can also work (some brands are harder than others). The plug is absolutely necessary for accurate shooting with .550-caliber bullets at longer ranges, and because the plug ensures an instant and forced expansion while the bullet is still at the breech, it greatly helps reduce fouling.
4. Use very thin 100% rag paper. The paper that forms the "patch" around the bullet must be strong, thin, and resistant to absorbing lubricant. It should be rag paper, if possible. Modern paper, made from wood pulp, should be avoided because it will soak up lubricant and then stick fiercely to the bullet, ruining accuracy and failing to control the buildup of fouling in your barrel. Some Enfield shooters use cheaper 25% rag paper, with apparent success. Look for a paper weight of 16lb or less. Bienfang 360 marker paper and Clearprint vellum are popular choices. The paper must be less than 2 thousandths of an inch thick. This is most crucial for cartridges made with .568-caliber bullets, because you only have 9 thousands to spare when making cartridges that must be loaded into a .577-inch barrel. If your paper is 3 thousandths thick, two wraps around a .568 bullet gives you a cartridge that is .580-inch in diameter. Good luck ramming many of those down a .577 barrel!
5. Cut three slits in the outer wrapper. Upon the fired bullet leaving the muzzle, these slits peel away from the bullet and act like a drag chute, pulling the paper away from the bullet without affecting the bullet's trajectory. Without them, the paper may not separate from the bullet, and a bullet flying downrange with paper residue still wrapped around it is not going to fly straight and true.
6. Choke and tie the cartridge tightly. The outer wrapper, with its three slits, must be "choked" absolutely tight. There are various methods of choking the cartridge paper (and some helpful YouTube videos, in fact) but no matter what method is used, the paper must be cinched and tied off in such a way that no gap remains in the "rose" formed. If there is a little gap left, molten lubricant will flow through it when the cartridge is dipped, and come in contact with the bullet and plug. This will cause the paper to stick to the base of the bullet, and be carried along on the bullet's flight. Believe it or not, some paper sticking to beeswax on the base of the bullet can survive 1000 feet per second of air velocity.
7. Form the cartridge tightly. The paper must be wrapped tightly around the bullet. There can be no gap along the angled cut of the trapezoid that allows molten lubricant to flow in when the cartridge is dipped. This takes some dexterity. It is easier if you have a hard wood mandrel sized correctly, so that when the powder cylinder is formed on it, the diameter is the same as the bullet. Otherwise you will always have loose-rolled cartridges. It also helps to cut your cartridge papers with very sharp scissors, or other sharp blade. Dull cuts leave a rough serration on the cut edge, which does not like to lie flat against the cartridge.
8. Use a sufficiently strong powder charge. Depending on your rifle, this may be more or less of an issue. As a rule of thumb, however, .550-caliber bullets need a strong charge to effect the instant expansion. Without instant expansion, the advantages of the .550-caliber bullet are lost. With less windage, .568-caliber bullets don't have to expand as much, and you can experiment with lesser charges. If you are using .550-caliber bullets, start with the service charge of 2F and work backwards. Italian reproduction constant-depth barrels seem to prefer 3F powder charges, while original rifles and progressive depth reproduction barrels do better with 2F or even 1.5F powder. My best shooting is with 1.5F "KIK" brand powder.
9. Dip cartridges in relatively cool lubricant. Even with good rag paper, if you dip a cartridge into very hot lubricant, it will soak into the paper and cause it to stick to the bullet. Historically the Enfield cartridge was dipped into molten wax at 230 degrees F. I will heat my wax until it reaches 230 degrees, and then take the pot off the heat for dipping cartridges. I will continue dipping in the steadily cooling wax until the wax begins to solidify in the pot, and then re-heat it back up. This ensures I am dipping my cartridges in relatively cool wax that will not soak into the paper. I then run the cartridges through a slightly warmed gauge to remove excess wax. My gauge for cartridges with .550-caliber bullets is .568-inch diameter, and .582-inch for cartridges with .568cal bullets.
10. Store your cartridges in a cool, dry place. Don't leave them in a hot car or in sunlight. This will cause the lubricant to melt, run, and soak into the cartridge paper. With pure beeswax this is not too much of an issue, but if you are using a thinner lubricant (tallow, modern muzzleloader lubes, etc), be careful to store your cartridges in such a way that the lube cannot melt or run. I left several packs of perfect Enfield cartridges in a metal ammo can, which I forgot about in the back seat of my truck in the Southern California summer. The lube melted and soaked into the paper, which then adhered to the bullets, and then the lube dried out; the result was paper virtually "glued" to the bullets. Getting the paper off was so troublesome that I ultimately just threw the bullets (with paper still clinging to them) back into the melting pot.
FOUR STEP TROUBLESHOOTING
If your Enfield cartridges are not shooting accurately, or your barrel is fouling rapidly, the problem is almost certainly one (or a combination of) the four issues listed here. Regardless of what caliber you are shooting (550 or 568), you should expect excellent accuracy out to very long ranges and, most importantly, no accumulation of fouling whatsoever. You should be able to shoot accurately until you run out of ammunition, or you collapse from physical exhaustion.
1. The bullet alloy is too hard. A very little tin or antimony in your lead will produce a bullet that will not expand when fired. Pritchett-style bullets must do a LOT of expansion, much more than other muzzleloader bullets like traditional "Minies" that are usually sized a few thousandths under the bore. Sometimes with "Minie" bullets, I could get away with using lead that is "pretty soft" but this is not the case with my .550-caliber Pritchetts! Pure lead is expensive and, in my experience, most people who try to sell me "soft lead" really have an alloy that may not be hard enough for casting modern rifle bullets, but is still far too hard for an expanding bullet. My recommendation is to not take chances with lead described as "pretty soft" and just pay little more for pure lead from the start. A too-hard bullet will not expand, or will expand insufficiently, causing poor accuracy but also resulting in rapid fouling as the gases pass around the sides of the bullet on discharge. This will quickly build up and difficulty ramming is the result.
2. The plug is failing. This is more important for .550-cal bullets than for the .568s but both will benefit from the many advantages of the expanding plug. As a caveat, if your Enfield rifle shooting usually consists of firing only 10 or 20 rounds from a clean rifle range bench at a target 50 or 100 yards away, you probably can get away without using a plug. The plug may, in fact, reduce the consistent accuracy of your groups at very short ranges, due to how it affects the weight and the center of gravity of the bullet. The history and purpose of the plug has been covered in detail on this site, but to summarize, the plug was a component of military ammunition that HAD to perform under dirty combat conditions, in all climates, to facilitate rapid and sustained firing, at enemies at potentially very long ranges. The plug was NOT designed to improve group sizes of bench-rest target shooting at short range. The plug causes immediate (or nearly immediate) expansion of the bullet, which reduces the accumulation of fouling in the breech end of the barrel; an important consideration for a soldier's weapon that may have to be fired dozens or possibly hundreds of times in battle. It increases the bullet's range due to the rapid expansion. So, all that said, if your Enfield is fouling (especially near the breech) after relatively few shots and your accuracy at longer ranges is poor, your plugs may be failing to effect the rapid expansion. Cartridges I made with plugs from Sculpey brand terracotta oven-cured polyclay were hopelessly inaccurate at long range (300 yards or so) while identical cartridges in all other respects but using a harder clay plug, performed beautifully.
3. The charge is not sufficient. Every rifle bore is different and there are numerous "versions" of the Enfield rifle-musket out there, including original rifles, Parker Hale reproductions, and a number of other reproductions made in Japan and Italy, including Dixie Gun Works, Pietta, Pedersoli, Armi Sport, Euroarms, and others. Tolerances and groove depths in all of these makers varied. This means it is often trial and error experimentation to determine what powder charge and bullet size/weight combination will work best in your barrel. As discussed exhaustively already, the Pritchett-style bullet must expand a great deal. If you are not getting any accuracy, your charge may not be sufficient to expand the bullet well into the grooves. Try increasing the charge. If you exceed the period service charge (approximately 68 grains 2F) with no improvement, the problem is somewhere else.
4. Paper is adhering to the bullet in flight. I think this is probably the #1 cause of inaccurate Pritchett-style bullet shooting. It is usually caused by poor construction of the paper cartridge, or by bullets that are not perfectly smooth-sided (i.e. with casting flaws). If any paper is clinging to the bullet after it leaves the muzzle, it will alter the flight of the bullet to some degree, either slightly or catastrophically. Making the cartridges very tightly, and choking and tying the base of the bullet without any gap, will solve most instances of paper sticking to the bullet. Using the right paper, dipping the cartridge in relatively cool lubricant, and cutting the slits in the paper in the right location, will also help reduce the frequency of stuck paper.
Authentic Paper Cartridges