I have been teaching forcible entry for almost 10 years, in that time I have seen a few injuries. It sometimes comes with the territory: bumps, bruises, and the odd black finger nail have happened when both members of the forcible entry team are not on the same page. One of the simplest mistakes that I have seen firefighters make that leads to injuries is holding the axe too high on the shaft. A lot of firefighters are thought to hold the shaft of the axe directly below the head. In my opinion this is an incorrect grip.
The reason that this grip is not favorable is because if the striking firefighter is off the mark with the swing by only a few inches the can crush their fingers between the shaft of the axe and the halligan adz. I have seen this on several occasions and a couple of times it has led to a black finger nail or a broken digit. This is a serious problem not only because of a member getting injured but on the fire ground the forcible entry operation is halted which could cause significant delays in entry, water on the fire, ventilation, or commencement of search and rescue operations.
To avoid this, ensure that your members keep their top hand at least 6" below the head of the axe. Lots of companies, to ensure that there members do not forget this, place there company identification colors or number at least 6" down from the axe head, this will be a subtle reminder to keep your hand down and it will also build company pride and ensure no other company walks away with your tools.