Building first Savage - Receiver advice needed

As I can't find the Savage I want (Model 116 Bear Hunter in 300WM), due to it being a "build to order", it has been recommended that I build my own. Was told to start with a used 110/111 series receiver and go from there. So, as Savage rifles are totally new to me, I have a few questions:

By the Savage catalog, I know I need a long action receiver for 300WM.
Do I just go by the action screw dimensions of 5.062, common to all Savage long actions?

Looking at the FAQ section of the forum, there seem to have been receiver design changes over the years. Apparently some long actions had magazine openings only long enough for short action cartridges.
Should I stick with a particular range of calibers from the donor rifle?

I'll be prowling pawn shops and guns stores looking for a donor rifle.
Anything in particular to look for in the way of common problems with long action receivers?

This will be me started on my search. I can worry about bolt head configuration later.
Lastly, ANY advice appreciated.

Call Jim Briggs at NorthlandShooters Supply. He advertises on here. He sells actions and can give you the correct information. Many have been caught in the change of design hassle as Savage built short action cartridge guns on 110 actions which caught people unaware about them when buying a rifle for a donor action. (count me as one). Jim will also give you other info you may not even know that you need to know. He is well respected on this forum. The price of an action will be less than a used rifle in most cases.

El Lobo

Jim is great but fyi I bought my donor 111 at Gander mountain fir $250 last year. They had another one on the shelf as well but yes it was used. Its tough to find an action cheaper than that.

You can buy the 111 blued or the SS predator action I believe. Either way contact Jim for new actions, they run $300-500.

Excellent!
Thanks for the lead on Northland. I will give Jim a call.
My only used LA Savage I've seen so far was a very well beaten .30-06 with an ancient Redfield scope. Gunshop must think it was a gem, as the price is $556!