All the test results you need in one photo.
About 10 feet with single shot of 38sp shot capsule filled with #4 and #12 shot, fired from a 2" S&W 442. Barely twitched until it was scooped up (with a branch) and tossed into the back of the truck. Very few, and very tiny holes in the hide so guessing most hit the targeted head. Nobody volunteered to skin the head to check for damage.
42" long with 12 rattles.
50 yards out of camp laying across the road while we were returning for the night in a tent.
My personal 2nd largest taken in SE Oregon.
#1 was also 42" but had 13 rattles taken in NE Oregon.
The usual Oregon rattlers are more often in the 18"-22" range with 4-7 rattles, at least from those I have run across.