Looked at Speers online data for the 170gr HotCor. Six loads listed but the only two powders I have on hand are R-15 and CFE 223. They're showing 2400fps with Power Pro 2000-MR out of a 24" barrel. May have to try some of that as it's 150-200fps quicker than other loads, but not sure how it would be in a 20" barrel. My experience with slower burning powders in short barrels is wicked muzzle flash. Brass and bullets should be here this week for me to start working. Gun isn't here just yet, waiting on that call from my FFL.