There is some fudging going on in the comparisons. If you want a custom action, buy it. If you are satisfied with a Remington 700, use one of them. But if you are going to make a comparison, make an accurate one.
The first thing that needs to be done is to establish a definition of "blueprint the action".
Enlarge and true the scope base mounting holes.
True the tenon threads, receiver face, and lugs.
Ream the bolt raceway.
Drill the front of the receiver for a pinned lug.
Open the feed port for an extended magazine.
Install bushings on the bolt body.
Install a firing pin bushing in the bolt face.
Replace firing pin and spring.
True the bolt lugs.
Weld the bolt handle to the bolt body.
Flute the bolt.
Install an M-16 extractor.
I agree 100% but that goes both ways. When I did "my" comparison I used a custom clone that was almost identical to the 700 Remington and came up with a $600.00 difference.
If you buy a Remington with some of the extras found on Custom actions it will coat more.
Blue printing involves Truing the tenon threads, facing the receiver face square to the bore, squaring and lapping the recoil lugs, and squaring the bolt face to the bolt centerline.
Any other modifications are strictly optional and don't have anything to do with bringing the action in
to accurate tolerances.
I sometimes do some of the other modifications for my rifles you mentioned simply because I wanted to not because I had to. Many of them I have never "had" to do. interestingly enough
I have never had a problem with the Remington extractor because I don't load over max loads and keep the extractor and chamber clean and working properly. I don't load so hard that I have to hammer the bolt open because it can break not only "any" extractor but also the bolt handle and the case head can be separated from the rest of the case. IT"S JUST A BAD IDEA ALL ROUND.
I also don't like lengthening the ejection port because it weakens the action and if I need a longer port I get a longer action. There are many other things that aren't necessary to blue print an action
and have nothing to do with the process they are just options that a person may want.
PS: if I wanted to do everything on your list, I would simply buy a Custom action and spend the money. I just don't want someone that can't spend money they don't have and possibly not build an accurate rifle when for very little they can get into a very accurate rifle without all the unnecessary frills foe much less.
I am not arguing for or against custom actions just for the comparison of the two in cost and performance. At the range or hunting Its not the action that impresses most but the little round hole in the paper or the perfect hit that counts and normally settles the argument.
Just saying.
J E CUSTOM