For those of us who do not really want to spend money on "made-in-China" stuff - the procedure described is also what I use now. It is also described in the Woodleigh Reloading Manual - might have also been in some earlier Nosler manuals and some John Barsness articles. Yes, probably not "dead nuts" accurate, but neither are bullets - even from the same box - if you are looking to be 30-ish or so thou off the lands, the actual bullet dimension and measuring differences probably go away or are insignificant - useless you are a world class competitive shooter. Everyone needs an excuse for a miss or larger than 1" group, though, from their store-bought or ex-milsurp rifle and gear.
There are / were many "no special tools" ways to "find the lands" - I used to Jiffy Marker a bullet - try it in the chamber - increase OAL - until I saw land marks - then back off until no marks - up to the reloader how close to get with his gear.