New BTCSS .223 should arrive in a few days!, Questions

Am very eager to be new Savage 12 owner. Just interested in paper-punching small groups. I reload for.223 already and shoot 69 Nos CC almost exclusively. All shooting semi-auto so far. With this bolt gun does anyone know the best COAL with Barnes 68-69 MB,s and Barnes 52-53 MB's? (Sorry, in the garage but I can't remember which exact weight they are.)

I found these Barnes Match-Burners on a lucky search of a site since it seems EVERY Nos. 69cc has been gone for a month or more. (How about this reloading supply panic? Are we having fun yet?)

Am hoping to work out to 500 yds. with this barrel and also get a high-grade .308 tube for exploring LR-Shooting a little later. The brilliance of having such a sensible routine to switch calibers was a big factor in the purchase.

In the same vein, does someone know definitively what the Throat-Length will be in this pipe?

Semi-Auto gun is 1-8 @ 18". BTCSS is 1-9 @ 26"..... This should be interesting getting back to cooking some loads for testing. Any "pet loads" out there that these Savages generally love?

Thanks for all input and standing by.