For the experts out there, does barrel length for a given caliber change what powder will provide better speed? In my case is there a benefit to using a somewhat faster, or slower powder, when using a shorter barrel (21" 338-06)? Not suggesting going outside the powders that typically work with a given caliber, just maybe leaning towards the faster end of those that would normally be considered for the 338-06. H4350 and RL17 are what I've been using, and they have worked well. Just curious if I should consider others (I have Varget and H4895 laying around).
................Whichever powders that are listed showing the top speeds from a 24" barreled 338-06, will also give you the best speeds from your 21" barreled 338-06. In other words, you load for that 21" barrel just as though you were loading for a 24" or a 26" barrel. The same is also holds true if loading for even the shorter tubes such as 20" or less.
Regardless of barrel length, whether from a 16.5" tube up to a 26" tube, the slower burners (where listed for a given cartridge showing greater speeds) generally across the board, will also give the better speeds in the shorter tubes.
RL 17 was primarily designed to give a velocity boost in the short mags. However, I read that it is doing well in other cartridges too.
