If you are in a hurry here is the summary – homemade wax slugs – don’t do it…
However, when I am told don’t do something, unless I know WHY I should not do it, my nature directs me to do it, and so this post will describe the common YouTube practice of homemade wax slugs and why they are incredibility dangerous (as well as a bad idea).
Basically a number of YouTube gun channels describe this process in some detail and many are led to believe wax slugs are a cheap alternative to conventional slugs and/or some devastating defensive or hunting round.
Basically a wax slug is where someone takes a shot round, pries open the crimp, and mixes hot wax with the shot. Either they drip wax into the shell, or they dump out the shot mix it with wax, and then repack it.
What then happens is the wax holds the shot column together longer so that it does not expand as much, therefore acting more like a slug than shot.
However, wax melts, and as it travels down the barrel it leaves a thin coating of wax on the bore. In a previous post about rifling we talk about the catastrophic effects of constricted barrels. Any observation of the thickness of a shotgun barrel compared to any rifled barrel will show the thin nature of smooth-bore barrels. They have NO tolerance for construction, and wax will very quickly build a dangerous level of coating on your bore.
If you shoot waxed slugs in your shotgun you will eventually blow your gun up, this will not only ruin your gun, but will also likely maim you for life.
I have a very high tolerance to dangerous projects because I am very confident in my own judgment and research skills, but just because something is cool and DIY does not always make it a good idea.
Commercial slugs are not very expensive, are readily available, do not contaminate the meat of game if you are using slugs to hunt, and will not open yourself up to very serious legal questions about intent in a self-defense shooting. They are also much more efficient and useful than wax slugs.
Additionally, shotguns are notoriously finicky about loads, they just do not have the same tolerances for home loadings as rifles or pistols do. Even if you are meticulous about cleaning all the wax out after every shot (which as a candle maker, I know how close to impossible wax is to remove), the changes to the weight of the load will also increase pressures inside the gun.
If you want to make your own loads – buy a shotshell reloader and get the satisfaction and self-reliance capabilities of making your own shells the safe way. Something like a lee load all is very inexpensive, makes a decent quality of shotshell, and allows you to make shot, slug, and buckshot rounds in your own home without risking turning your gun into a pipebomb.