Just starting load development for this brand new rifle...first Savage and excited.

My super accurate load (for 18" Shilen, 1-8, AR) of 69 g. Nos. CC over 24.3 of 8208-XBR [Note: Over-Charge by 0.5 Gr.!, Work up-to your own load!] @ 2.260 just will NOT shoot in this half-mile-long 26", 1-9 barrel, Savage Barrel!

I just loaded 10 Each of 69 Barnes Match-Burners at 2.334" OAL with the following VV-N135 Charge Weights. I measured chamber to be Positively 2.344 OAL with these bullets at Contact With Rifling (not Stuffed). I'll try them 0.010-0.011 off and see how they fly..
22.0 g.
22.4 g.
22.8 g.
23.3 g.
23.7 g.
All primed with Tula 5.56 SR-Mag' Primers.

I think problem with my previous lights-out AR15 load was the bullet-speed being too fast for a 69 g. Nos or barrel-harmonics. Velocitiy shift from 18", 1-8 twist to 26", 1-9 twist was exactly 300 FPS. Where the AR was shooting at 2,700 with low deviations and less than 1/2", the same cartritridge in new BTCSS was making high 2,900's to 3,000 in the longer tube and struggling to stay at 1" (100yds).

Anyone care to guess what the best charge above will be for 100 yd. groups. I'll come back on in a week or two with Chrono. numbers, etc.