Re: AR-15 Hand loading tips
To start off here, recognize the fact that these aren't bolt guns, and that many of the accepted techniques for tightly chambered bolt actions will cause problems in an AR. These are different. I'd suggest both of you guys purchase and use a chamber gage, and use full length sizing at the very least. Any of several makes of shouldeer bump gages will help you set your dies up to ensure that you're moving the shoulder back .003"-.005", which is what you want for a semi-auto. The bolt guns run with .001" or .002", but that's an invitation to a problem with a Service Rifle. Small base dies may not be needed, but they'd be what I'd suggest, just to avoid any potential problems, especially related to body diameter after resizing. The 1x9 twist is going to top out with the various 69 grain bullets available, while the 1x8 can use the heavier 77s and 80s without a problem. Among HP Service Rifle shooters, the split is about even between Varget and RL-15 for bullets of 77 grains an up. They'll work for the 69s as well. I'm running N540 for my heavy bullets right now, and am very pleased with it. For ther 69s, I might also try N135 or N140. For lighter bullets, they'll work just fine in these twists, but I'd step up to a faster powder, such as N133, N135, Benchmark or H-322. Pressure signs are going to be the same sorts of things you'd see in a bolt rifle with regards to primers, case head appearance, etc..
Beyond that, just don't hesitate to ask questions here. Plenty of good info from folks who've already been down the road. You might also want to check out the USrifleteam site as well, and see what you can find on the Service Rifle boards pertaining to reloading.
Hope this helps,