Reminds me of the time I was rabbit hunting in the desert with a .22 when I was 19. I saw a cottontail leap out from behind a sagebrush and stepped foreword as I fired. I hit the rabbit then looked down to see what the spongy feeling thing was under my foot. It was a rattler! I jumped back and shot it too. Double whammy with two shots.
Well, I hope to tell you, a rattlesnake bite is infinitely worse than a copperhead (even if the copperhead manages to get the venom in). My only question, did you field dress the rattlesnake? They are delicious! Tastes like frog legs.