Yeah this is what I'm saying fellas. I'm slightly offended that Van Bilderass, one of the best and most intelligent posters here thinks I'm lying
I'm not one to brag about my physique, I certainly wouldn't lie about it, or getting a 1.5" arm pump which is NOTHING special IMO.
Maybe it's fair to add that when I was natty I might add only 1 inch from a good pump. On test/deca, easy 1.5". Throw in my secret ingredient (Snickers ice cream bars pre workout) and this is where the magic really happens 
It wasn't meant to offend but what you're describing IS special IME. I think there's probably some self trickery going on somehow. Do it again, take the tape measure to the gym, measure before workout in the locker room, pump your arms to the max and then measure again. Make sure the tape is placed exactly in the same spot, not crooked, without any slack due to sweaty arm or whatever. I think a .75 gain is more realistic for an arm that size, from what I've see.
Galeniko, take measurements too, I want to hear what you gain pumped.
1.5 is crazy. Anyone, take a tape measure a measure the arm right now. Then put 1.5 worth of slack on it see how much bigger the arm has to get fill it. It's an enormous gain.
Uhmmmmmmmmmmm, have you ever gotten a real good pump before? Especially on AAS?
lol
I guess you get an "easy" 2 inches by pumping up? You too bro, measure again and don't trick yourself by measuring with the tape on all crooked.

If someone puts a high quality video on here showing pre and post pump arm gains of at least 1.5 I'll freely admit I'm a complete dumbass.

BTW, this topic reminded me of this study. It may have some limitations but may be interesting nonetheless. Not about pumping per se, but about carb loading which makes most "feel fuller".
Effects of carbohydrate loading and weight-lifting on muscle girth.
Balon TW, Horowitz JF, Fitzsimmons KM.
Dept. of Diabetes, City of Hope Medical Center, Duarte, CA 91010.
Bodybuilders have used different carbohydrate loading regimens in conjunction with resistance exercise prior to competition in the belief that this would result in increased muscle size. To investigate this possibility, muscle girth measurements were obtained from nine weight-trained males before and after a control (standard isocaloric diet) and an experimental trial (carbohydrate loading). The latter regimen consisted of 3 days of intense weight-lifting while the subjects ingested a diet of 10% carbohydrate (CHO), 57% fat (F), and 33% protein (P), followed by 3 days of light weight-lifting and a day of rest while ingesting a diet of 80% CHO, 5% F, and 15% P. The control trial consisted of an identical weight-lifting regimen while subjects ingested an isocaloric (45 kcal/kg BW/day) diet. Body weight and girths (forearm, upper arm, chest, thigh, waist, and calf) were obtained before and after each trial in a relaxed and flexed state. The results indicate that an exercise/carbohydrate loading regimen had no significant effect on muscle girth as compared to the control trial. It is concluded that CHO loading has no additional advantage to enhancing muscle girth in bodybuilders over weight-lifting alone.