I'm 66 years old. With that caveat, I'd go with a custom receiver to begin with. But I'm not worried about parts availability fifty years in the future. Add to that, the strange metric barrel threads in the Howas, the trigger/safety problems in the Remingtons, and the sheet metal magazine lips in the Savages.
If you want a true custom rifle, you better start out with a custom receiver, which is the heart of the rifle. Just be sure that you choose which receiver, very carefully. There are questions surrounding some of the cast ones.
I have had one Howa, a Weatherby Vanguard Deluxe, and have had several Rem 700's, from a 300 Sav. up to a left hand 338 RUM. The Remington publicity about three rings of steel is pure bunk, IMHO. The flimsy one right next to the case head, is actually soft steel.
I watched an old G.S. Oxy Acetylene gas weld a new one onto a Remington Bolt head, after checking with the Factory. They can't put hard, (brittle) steel next to the brass case head, in case something goes terribly wrong. Like what just did happen to that particular rifle. It has to be able to peel back rather than turn into shrapnel. Just look at a Rem. bolt head to observe this.
Putting in the correct (of the three?) Sako hook extractors helps, but a custom action will already be there, using American barrel threads, for the sake of the smaller shops.
