I've done it the timed way before by setting a clock with a second hand directly behind the torch flame so I can count seconds the case shoulder is engaged into the torch flame. Still gotta figure out the correct number of seconds one way or another if solely relying on the second hand. So just be conscious of the fact that the number of seconds in the flame will be dependent on the temperature of your flame (Map gas burns much hotter than a Propane torch - I use Propane), the size of the casings, the length you set your torch flame to, the location you engage the case shoulder in the flame, and whether or not you fart during the process.
For my .223 Rem cases, and the way I set my propane torch flame, 5 1/2 to 6 seconds is about right. But for 280, 7mmRM, 300Mags, 338Mags, the time will be longer. So figure out how many seconds by watching a few begin that faint orange glow on whatever cartridges you're annealing, and then maintain the same flame length and insert the rest of your casings into the same location of the flame for the same number of seconds; you'll be pretty darn close. Change the length of the blue flame from your torch, or where you place the case shoulders into that flame, and the proper length of time in seconds will be a little different. I tend to believe there's some latitude in the amount of annealing applied to the case shoulders, without severe negative consequences. But I can see David Tubbs, Erik Cortina, and competitive shooters striving for the utmost consistency and spending $500 or more for an automated annealing machince. It's a living for some of them, and to compete with the best of the best, consistency is critical.
