Bottom line: In my testing with a hunting rifle and factory hunting ammo, I could detect no difference in accuracy or velocity either with or without tape.
Details:
Before I went on a hunt in October I conducted several tests with tape on and off the muzzle since the outfitter recommended I tape my muzzle. I conducted the tests with the rifle and ammo I intended to take on the hunt; these tests included velocity tests with a chronograph, and accuracy tests at 100 and 200 yards. The rifle I tested with was a Dakota 76 using Federal ammo with the 300g Barnes TSX bullet; note that I was testing with my hunting "rig," not a 1000 yard benchrest competition rifle. This rifle / ammo combo normally places 5-shots in just under 1" groups at 100 yards.
So with this rifle and ammo, I could detect no difference whatsoever in velocity or accuracy, shooting with or without black 3M electrical tape on the muzzle.
I tend to agree with people who say that the column of air in front of the bullet, when compressed and pushed through the bore upon firing, probably blows the tape off the muzzle before the bullet can touch the tape, regardless of how tightly the shooter wrapped the tape on the muzzle.
As a result I will probably put tape on my muzzle every time I go hunting, regardless of the weather.
While I may conduct the same test on a different rifle if I were to go long range prairie dog hunting, at this point I would not expect to see different results than I outlined above since I believe that it is the air column that blows off the tape, not the bullet.
