Specific questions for a 223 pushing 69 gr Sierra Matchkings. I have a 1-9 twist 26" heavy barreled model 12 Savage in 223 set in a McMillan stock and I'm looking for facts (mixed with opinions I'm sure) about the maximum effective range for this barrel length/twist rate/bullet combo. By maximum effective range I mean how far before it goes transonic and become unstable? I know that is purely dependent upon the speed of the load obviously. I have Varget, H4895, IMR 8208XBR, H335 and H322 on hand and am going to try and find the best speed/accuracy combo with this set up and I'm wondering if one of you fellow shooters has about the same if not identical set up running the same bullet and if you do what have you found to be the maximum effective range of this combination and what type of speeds are you able to attain? Looking to try this out for some fun shooting at steel, some longer range coyote sniping as well as some longer range Prairie Dogging. Thanks.