Also have a Griffin & Howe custom Springfield, which like many was apparently built on a 1903 "match" barreled action. I can confidently state this because the the NRA Match models had shorter throats, designed so the match ammo actually contacted the lands when chambered. It shoots VERY well with the lower-magnification scopes I've used in its 7/8" G&H rings, which have included the rifle's original 2.5x Lyman Alaskan, and a Leupold 4x "reproduction Alaskan."
Was your G&H rifle built with an NRA Sporter barreled action or a M1903 National Match barreled action? Both utilized Star Gauged barrels, but the NRA Sporter barrel has a slightly heavier barrel contour than the Service rifle barrel used in the NM rifles.
First I ever heard of special throat configurations in NM or Sporter barrels. I always understood the match ammo to be configured for a perfect fit in the standard Ball Seat throat as used in all gov't .30 barrels. I guess I'll be doing some chamber casts on my Springfield collection, which includes their target rifles and service rifles and an NRA Sporter. You got me wondering now! (I will say that the throats in all of them seem to have the same throat, as my standard go-to accuracy load with 168 Matchkings works universally. I even keep a dummy round in the die box to ease setting of the same OAL when switching back to that bullet. With an array of rifles like these I'm forced to full length size all the "universally applied ammo" and I seat the Matchkings to the same length. Luckily none of them have throat erosion issues that would dictate different seating depths.)
"You can lead a man to logic, but you cannot make him think." Joe Harz "Always certain, often right." Keith McCafferty
