The classic one day arm system, that The Pumpster offered, had been responsible for 1/16 to at least 1/4 inch(or more) permanent growth on some men. I've seem a few guy's gain from it. Can also be used on the delts & calves with effective results. Doesn't always work that well with larger muscle groups.
The game plan is to set aside a full day, usually 2 day's before and 2 or 3 day's after a regular workout. Taking a protein shake(s) will be a lot easier than trying to eat a full meal during the day, though a good breakfast is encouraged before starting. The idea is to keep a new supply of blood with-in the arms all day. At each hour (on the dot...important) a light set of tricep and bicep (1 to 2 sets each SS'ed usually...most say 1 set only...10 reps) are done. Do not grunt out the reps, these are just light pumping movements, with a weight that can be easily handled. Do not go anywhere near failure, probably 3 or 4 reps before. You do not want to over tax the CNS in this method of training. Defeats the whole purpose. The usually length is 8 hours, arms every hour. This can surprisingly be draining on the nervous system if any more is done. But feel free to experiment on you self's. But the main mistake most guy's make is of using too much weight. This is light volume training. Your doing set's, but one hour apart. Good Luck.