chicagojoe, Shortening a barrel and doing a crown job is not particularly hard to do, but getting it exactly right might be a challenge without correct tools.
LOL, I basically use a tubing cutter, hacksaw, and lee brass case trimmer.
Tubing cutter I use to score a mark around barrel where I want to cut.
hacksaw I use to cut along line made by tubing cutter. I might take the barrel to a 1" belt sander to smooth out or correct a cut.
Lee Case trimmer tool I use to cut the crown. WHAT?????? you may ask. If you have a collection of various diameter spindles for the case trimmer, you can usually use spindle one caliber lower than your bore. For example, this morning used spindle for a 243Win on my case trimmer in my 25 caliber bore. Mind you it was a loose fit, so to remove looseness and protect the rifleings at same time, I cut a piece of brass shim stock that fit around the spindle. Inserted brass shim in bore and lubed spindle and worked it into bore. Don't have a 1/2" chuck on my drill, so clamped a visegrip on the lee cutter, applied pressure to end of cutter and began turning it. Around 100 turns later, had a decent target type crown on the muzzle. You might be surprised how well a Lee Case Trimmer will cut/shave barrel metal.
visit surplusrifleforum.com and check their gunsmithing section. You'll find a sticky on this technique for crowning a barrel.
But as earlier poster wrote, gunsmith should not charge that much, so you might be wise to let him do it.