While some might claim that shooting thistles is neither hunting nor particularly difficult, I believe there is a strong case to be made for the sport as both challenging and dangerous. Challenging because the game is quite small and dangerous because thistles often run in packs. Attempting to get a good position to take out a single thistle head may result in damage to the legs or arms by a second or third thistle which one plops down on unawares.
For hunting these dangerous flowers, I highly recommend something in .17HMR or .22LR. The former, upon a direct strike of the thistle’s head usually results in a most satisfying explosion of petals. The latter, while not moving at nearly the velocity, does the same job for about 1/6th the cost per round of the former.
Quick follow-up shots to put wounded flowers out of their misery are sometimes needed, but the speed of a bolt-action repeater suffices. I use both a bolt-action repeater and a semi-auto rifle and find them equally capable for the task at hand. Shooting thistle heads with a pistol is a challenge in itself and not to be entered into unless you are prepared for disappointment. The kill zone on the heads is quite small and shooting a pistol rather than a rifle introduces additional variables to the hunt. However, if you have determined that hunting thistles with your rifle is no longer a challenge, switching to a pistol might be just what you need.
I usually engage the thistles at distances of 30 to 50 feet, though longer shots of out to 150 feet or more are not unheard of. The range at which I engage the thistle heads is often dictated by the terrain and the weather. Closer shots on windy days are a must since properly gauging the swaying or even oscillation of the thistle heads can complicate an otherwise simple shot.
While the thistle heads which have expanded into a bright lavender head which is 3 or 4 inches across are easy to spot, the heads which are about 1.5 to 2 inches across and tightly packed actually make better targets. The larger, looser heads will often absorb two or three shots before collapsing, while the smaller heads are rarely able to survive a single hit without catastrophic results.
Thistle hunting trips can be as short at a few minutes or can occupy an entire afternoon. Hunting in groups is to be encouraged. No special licenses are required. Not all types of thistles are suitable for hunting. Always follow safety rules for handling your gun–and any thistle heads you may wish to recover as trophies of the hunt.