Darrel Holland with his "Building a Tactical or Varmint Rifle" (American Gunsmith Institute) perhaps it is a great source for you.
You can see how he build the rifle. He use a "V-Block" of alumunium that glued in into the syntetic stock to "hold" the barrel (at straight tapper-shoulder area).
I just worry why do you choose a Springfield '03 action for this reason. If you want an accurate rifle for hunting purpose i don't think you need "extra treatment" like barrel bedding (=floating the receiver) and a #8 countur barrel that weight 7lbs for 26" length....
So, i assump you want a "target rifle"... Please correct me if i'm wrong.
If you want to build a target or benchrest rifle (supposed to be very accurate), i don't think the '03 action (or other old military bolt actions like '98, Enfield, etc) will fit the needs. It doesn't has a rigid structure and has very slow of lock time because of the design. (the pin travel is too long, the firing pin sets is too heavy and "slow", trigger mechanism design, etc...,even you then use like David G. Tubb's - Speedlock system and other replacement trigger sets).
You also need a good syntetic stock or perhaps a laminated stock for "stability" reason, because i guess you can not use a wooden stock for this "barrel-bedding block idea".
If you didn't have gunsmithing skill and a lathe machine, i don't think you can do it yourself. I don't know what caliber you want for your rifle. But i guess you want a "high power rifle", so the recoil lug (of the reciever) bassically must be right in front of (and the lug surface must contact) the front side of the block. This mean you need to remove the existing recoil lug, except you add "another" recoil lug on the barrel (as a primary recoil lug).
You know that Springfield has integral recoil lug at the bottom side (not as like Rem700).
If not, better you stay with floating the barrel and bedding the receiver...(as a "conventional" system - commonly used).
With your heavy barrel countur, perhaps add a 2" bedding for the barrel except of bedding the receiver (to help more rigid structure).
Glass or Steel Epoxy, both fine.
Hope this help and have fun.
Please apologize for my poor english since it is not my own languange.
Sebastian.
