I recently asked on this board about recommended powders for the .270 Winchester. The majority of responses suggested 4831 and 4350 powders, and this recommendation is also made by some gun writers. Recently, I purchased a new .243 and looked up load recommendations. IMR and H4350 were suggested for 100 gr. bullets. I was preparing to load some ammo when Hodgdon revised their recommended 4350 loading by reducing it a couple of grains. Said there had been pressure spikes with the old loading. I looked high and low for an alternative and found a load published in an IMR handbook calling for 47 gr. IMR 7828 to push a 100 gr. bullet out of a 22 inch barrel to 3050 fps. This loading had the lowest pressure on the IMR table for 100 gr. loadings. H1000 loading data looked almost as good. I suspected that there might be accuracy problems with the slow powders but bought an experimental pound of 7828, worked up to the 47 gr. loading and started shooting groups. Consistently put 3 shots in 5/8 inch at 100 yards. This has encouraged me to forego the 4350 and 4831 in my .270 and work with RL22 and MagPro when weather permits. I am curious, though. Why are most handloaders using faster powders in these slightly overbore cartridges? Seems like higher velocity, lower chamber pressures and decent accuracy are all good traits. Are there downsides to the slower powders that I haven't detected?
