just some random thoughts on the .303:
Ruger did have a run of #1's in the caliber a couple years ago, and if one were interested in maximizing the cartridge potential, that would be a good place to do it:
http://www.gunbroker.com/Auction/ViewItem.aspx?Item=481388361I have a #4Mk1. It taught me that headspace gauges were invented for a reason
It also educated me, that #4's were designed with interchangeable bolt heads, so one can easily adjust headspace. I needed a replacement bolt for mine, and after some testing of different heads from Gun Parts corp, I managed to get the rifle where it would resist closing on a "no go" headspace gauge.
I have only shot factory loads in it, but it seemed to shoot well, so some handloads are likely for this summer's testing.
