I am a big fan of mechanicals. I hope I dont regret saying that on this forum. I have found that as long as you make sureyou areusing a matching grain fieldpoint that there is really no need to sacrifice your Mechanical Broadheads for practice.
Truthfully, I've found the same thing.
Of course, tying them up with dental floss should keep you from ruining it... though I agree; it's pretty much a waste of time and energy.