If a SpitFire 125 will pass through a moose you will not have problems with an Elk.

Mechanicals will loose some energy opening up, but with almost all bows in todays market place, they have excess energy to spare. What you need to worry about is the KE of your bow/arrow combination. I know from research, that the spitfire only looses 3 foot pounds of KE when opening, so I do not find where the problems are with mechanicals (the spitfire). People should not class all mechanicals together, some are good and some are not.