About to start the process of building my first AR and I have decided to go with a 20 Practical. I am trying to decide what bullet I want to run so I can choose an optimal twist rate. I'm debating between the 35 berger, 40 berger, 40 vmax, 39 SBK. This will be a coyote rifle 99% of the time, and almost always in calling setups. I have some H4198 and IMR8208XBR on hand I plan to start with. Rifle will be Rock River and Aeroprecision based. Planning to run a 24" barrel. Unsure on mfg yet. So my questions are... What is everyone's experiences with the bullets listed above? What are your pet loads? Velocities? Twist rates? Who makes a good AR barrel in 20 cal?