Man, that is a weird choice of words.

First, “dumb” is the inability to speak, either permanently or temporarily. People once thought that if you could not speak you must be stupid, so dumb kind of got mixed in there with stupid. But now that we look back and can see that we were wrong, it is pretty stupid to use “dumb” in the context you selected.

Now for the irony, I’d say that you’re making a stupid decision to take your chances at a turkey, simply because you don’t want to damage your blades with practice. As Hunting Son mentioned, you’ve already got an investment in your set up. By the time you get into the woods, scout, build a blind or stand, call them in and finally take a shot. Sounds good, but what if you miss? Was it your shot, did you do something different without knowing, or was it those blades? Those ones that are now damaged, and still no turkey. If you miss because you made a bad shot for whatever reason, that is hunting. If you miss because you were lazy and cheap, that’s stupid.
Do the honesty test; If you do miss, can you be honest to others about why and not be embarrassed? If so, you’re doing okay, if not, change something about your MO.