Annealing cups, handy for erm, well annealing and we all know about annealing case necks don’t we?
The idea being you uniformly heat the neck of a case to a set temperature taking great care not to heat the body excessively, then cool the case and you have softened the brass to the original manufactured state. Why bother? Well brass work hardens with repeat firings, this leads to inconsistent neck tension and a possible fall off in accuracy plus in theory you can get many more firings from brass that has the case neck periodically annealed.
I have built rotary annealers in the past, the first one was an interrupted motion device using a Geneva Cross drive and I am currently building a constant motion system however such systems are not for everyone and a very workable alternative is an annealing cup, stick one of these into a cordless drill, drop a case in and mark just below the neck with Tempilaq (I use the 650-750F indicator painted on) then spin the case in the drill with a gas torch applied and watch for the Templiaq to change colour, at this stage the neck has reached the required temperature and it is just a matter of tipping the case out and repeat the process. I tip the heated case into cold water as it makes the Tempilaq easier to get off.
You can also do this without Tempilaq by looking for the colour change to just below the neck, if the case dulls off you have heated it up a tad too much.
These cups are sized for 6,5-284 which the Schultz & Larsen is chambered for and .223 The aluminium body also helps to stop the rest of the case heating up excessively.
Guess what they are made out of, I really do need to get out more….