Heh. That goes against all rules for good muscle hypertrophy.
Likely if you see any size gains in your arms from doing that, it's because the muscles are so damaged afterward that the tissue becomes swollen with fluid. In the long term, that kind of routine will probably develop scar tissue on your muscles, making them worse than before.
Fact: New muscle does not and can not grow over night. This is partial proof that the swelling in your arms is likely from tissue damage and fluid replacement instead of new muscle. Muscles do not grow when you work them, they get torn. 95% of muscle growth is done while you sleep. This process does not typically even START until 36-48 hours after the workout. Muscle does not recover (hypertrophy process) in 24 hours, it takes at least 72 hours after the recovery process begins. At least.
The gains you are seeing are fluid from the swelling of the trauma you caused your arms. When you recover, I wouldn't be suprised at all if you go back to your normal arm sets, and you've made ZERO gains in weight or reps, proving zero muscle gain. Heck, I wouldn't be surprised if you went DOWN in previous capabilities. It's just like how your arms look pumped directly after you work out, it's just extra blood in your muscle tissue, it's not actual muscle being created. Which is why your arms are actually going to be smaller (albiet barely noticable) for the next couple of days while you recover. This process is a more long term injury to the muscle.
Slow and steady wins the race.
Further more, it's rather disapointing to see people going after sheer size when it comes to excercise and lifting. Bulk does not equal strength. Dense muscle, muscle balance, strong support muscles and stout ligaments equal strength. All of these things would be damaged by a routine such as this.
I'm not trying to knock anyone who's tried this. But everything I've ever learned about muscle building and lifting weights goes AGAINST this type of excercise. There are better ways to add bulk to your person, get stronger, and shock the central nervous system. I would never recommend this work out to anyone.