If you guys need help getting started the right way on neck turning, send me pm's, glad to help out. K&M neck turning set up is the least expensive way to go, will get you Match grade turned necks on the first attempt.
No need in buying junk. Nice thing about the K&M is that if you want to sell it when you done, people are standing in line wanting to snap it up.
Thick necks can be a problem. YOu need .004-.005 clearance from the chamber for good bullet release. It has been found that tight clearances create larger extreme spreads in your velocity.
Also, it is prudent to anneal after sizing down, I have always used a propane torch, bread pan, and #2 wood lead pencil.
Couple of pointers, accurate measurements can not be made with calipers, you need a micrometer
https://www.ebay.com/itm/iGaging-0-1-Digital-Micrometer/182662261067?hash=item2a8784e94b:g:ciUAAOSwfRdZGzH0
https://www.ebay.com/itm/0-1-Tube-Micrometer-0-0001-Graduation-Carbide-Tipped-Neck-Ball-Spherical-Anvil/292970589868?hash=item4436686eac:g:Y78AAOSwVRBbzavF
While these measurments above are not top name brand, they will serve a shooter very well that is turning necks.
A tube micrometer is worth it's weight in gold for helping to quickly adjust neck thickness on the turner.
The gunsmith should be able to give you a reamer print or a print # that you can use to call the reamer maker and get an emailed copy of the reamer print. This will give you the exact dia of the neck, and tell you if the neck has any taper. The print will also give you a max length of the case so you will know where to trim your cases.
IN the early 80's, we turned necks by making a hail mary cut, then seating a bullet, then measuring the outside dia with a caliper...what a hap hazzard way to do a project with helter skelter results.
Set yourself up with a K&M neck turner, mic, and tube mic, and your project will go together like peas and carrots!