Those who have zero experience at it, say it can't happen.
Those who have actual experience say it works.
I have actual experience, and it didn't work in my case. NAA .22LR mini-revolver, 1 1/4" barrel; CCI shotshells; snake was quite small, perhaps 2 feet long; range was less than 3 feet. The snake was centered in the pattern, and slithered off into the grass after I shot it. That was the last time I used that gun on snakes.
Perhaps it died later, but it certainly wasn't immediately incapacitated, and if it wouldn't kill a snake as thick as your thumb from less than 3 feet away, then it's certainly not going to do much to an eastern diamondback other than make it mad.
Now, out of a longer-barreled pistol or revolver, it might do a little better, and better still out of a rifle. Even better than that would be a .38/.357/9mm/.45 shotshell out of a centerfire pistol or carbine, as there is a marked difference in shot size.
For this application, something like a Taurus Judge loaded with .410 birdshot would probably be better than a .22.