It's hard to anneal short action cases by hand as they heat up too fast. .338LM for example, is doable. But a cheap way to put together an annealing setup is the following:
Note: this is a rather simple explanation and I'm sure there are YouTube vids that explain this in more detail, but I'm writing this to at least give you an idea of how it works.
- electric drill
- set of sockets (for a socket wrench)
- propane torch
- tempilaq 750 (optional but advised)
Take a piece of brass and check to see which socket it fits best into. You don't want it to be so loose that when it spins, the brass just falls out. You also don't want it so tight at that when the brass heats up and expands, you can't dump it out via gravity.
Setup somewhere with good ventilation but not breezy or too bright either. Mark a case with tempilaq, if you have it, from the mouth down to the shoulder and let it dry. Hook the socket up to the drill (most socket wrench sets will have an extension) and place the brass in the socket. Ignite the torch and set it up so that it's stable for hands free use.
***it's wise to wear eye pro while you do this***
Now let the drill rotate at a fairly slow speed - not the slowest, but also not whipping around. You just want the brass to rotate about 360 per second or so. Lower the brass into the flame so that it's centered on the line where the neck meets the shoulder. You don't want to do just the neck nor just the shoulder or any lower. The trick here is to watch the tempilaq and see when it starts to melt, which is the signal that you've reached the 750 degrees needed to properly anneal the case.
For .308WIN brass this usually takes a 2-3 seconds at most. You don't want to under anneal the case because that won't do anything for you. Overannealing is bad and letting the rest of the brass get too hot is really bad. If the case base and web get annealed it'll be too dangerous to shoot. You'll have to experiment with the amount of time under the torch to get it right, but once you've figured out how long is necessary it's as simple as just counting it off for each piece you do. A visual reference that I often look for is the brass around the heated area to take on a greenish hue.
Either way, as soon as you reach the correct temperature, take the brass out of the flame and dump it into a non-heat sensitive container like a ceramic bowl or metal tray. Some say you should quench it with water, others say you don't need to. Experiment and see what works best for you. But above all, remember you're dealing with an open flame! Make sure there are no combustibles around and that the torch can't easily get knocked over and roll onto a carpet or some shit. You'd be surprised how many people do dumb shit like that. My workshop is pretty tiny at my current place, so I've been doing it in the bathroom on a tile floor in reduced light with the fan going.