Timney triggers usually require removal of both stock wood and also some metal in the trigger guard and/or receiver. Also, after fitting, they need to be thoroughly checked out to make sure there is no interference after the stock is replaced and tightened down. While the job is not beyond the capability of any reasonably competent person, I can see why the makers say to take it to a gunsmith, as there are some potential problems.
Before installing the trigger, realize that you may have to make permanent alterations to the rifle. If that bothers you, don't do it. Then, read all the instructions carefully. DO NOT go adjusting the trigger until or unless you fully understand what is involved.
Sear reset is very important, especially if you are going to use the standard safety. Cock the rifle and engage the safety. Pull the trigger. Release the trigger, then disengage the safety. The firing pin must not drop.
If it does, DO NOT stone or file anything. Take the gun to a gunsmith.
Jim
