Re: Bushmaster Varminter
First things first, what bullets did you want to use? With a 1x9", you'll be able to use most anything up to and including the 69s. What did you want to use these for? Hunting, or target work? In general, with the heavier bullets (69s) I'd go with Varget, RL-15 or N140. With the lighter 50-55 grain projectiles, stick to a slightly faster powder like H322, Benchmark or N133.
Beyond that remember that full length sizing isn't an option, it's absolutely mandatory. Stick to tougher primers, like the Rem 7 1/2 , the Wolf 5.56 or Small Rifle Magnums, or even the CCI #41s. I'd also strongly suggest using gages to make sure your headspace is right and you've got sufficient clearance for proper chambering. These aren't bolt guns, so don't try to load for them the same way.