I am not aware of Sierra ever making a .312" dia bullet in any weight. That said, Sierra is never a bad choice even at .311". On my 1935 FN Peruvian I use Hornady .312's...the 150 flat base for hunting and for targets, the excellent 174 bt sold by Grafs, #3031G. If you are shooting an old Argentine, by all means, stay on the safe side with the slow bulky powders you mentioned. If you have a stronger rifle, you will find RL-15, H4895 burning rate will give you good velocity, low e.s., and superb accuracy. I shoot steel to 600 yards with mine, it's just sporter weight. Generally speaking, in a strong action, what works in the .308, works in the 7.65...there being only 2 gr more internal capacity. Have fun with one of the most under appreciated cartridges out there.
