You can rent the gauges you need pretty cheap on the net if you need them. I headspaced my 6.5 PRC that’s a tikka action and an xcaliber barrel and nut system it was pretty easy and it turned out nice. The nut doesn’t look to bad at all. You have to go after the stock with a dremel a bit because of the nut but that takes about 5 min or so.
So the common question is why? Well at the time I did it you couldn’t get a 6.5 prc on a tikka so I went about it myself. It’s a 21” barrel shooting 156 bergers. The results are in the picture that’s a 3 shot group.
What twist rate did you get? Can't decide between a 1 in 7.5 which seems to be ideal for the 156, or a 1 in 7 for a possible future monometal on my 6.5 PRC build.