I have replaced a couple of these. Not too hard if you like fixing things. If you haven't done them before watch it on youtube; I believe you can do it.
.44 mag is fine for deer, for as far as most of us can accurately shoot with a handgun. I use a S&W with the 8 3/8" barrel and open sights. .44 magnum is just a great caliber.
I have the Milwaukee trimmer. Works very well, and I didn't have to buy any batteries because I have 5 or 6 batteries for a drill, impact wrenches, angle grinder, etc. Now we have the leaf blower also. For the trimmer, battery life is pretty short. I think if you have a farm or a lot of trimming...
For the kids. I have a trailer and come pick it up. My budget depends on what you have but willing to pay a fair price. Indianapolis in Elkhart County, but willing to pick up in other locations.