I finally just threw in the towel on trying to do it and went with a higher velocity (~ 1200 fps). It's been my experience handloading, that a 9mm 124 gr lead bullet is a real "pistol" (groan - bad pun) to work up a decent 1100 fps load for. Lighter bullets would have a more pronounced and less easily predictable drop due to the fact that lighter bullets have less mass, and that makes them shed more velocity at any given range than a heavier bullet that has more mass. Due to slow initial velocity, subsonic rounds have a more pronounced drop at any given range. The short answer to the "what range" is probably 50 yards max. Other factors are rate of twist, the actual air condition - "heavy" high humidity air has more of en effect than cool drier air. A truncated cone profile seems to work the best - hollow-based wadcutters seem pretty immune to the effect - and round nose lead seem to fare the worst. The profile of the bullet also has a lot of influence on how it behaves when going trans-sonic. Usually you can tighten up a group by either increasing the powder charge and bumping the velocity up a bit so it goes sonic in the muzzle and stays sonic the entire journey, or dropping the charge so all of the rounds stay subsonic. If you load near borderline with slow burning powder- say 1150/1175 fps or so, that's one of the causes of those pesky 25 yard "flyers". The worst case is having the bullet go supersonic just as it leaves the muzzle, then falling subsonic downrange. That eliminates the problem with the buffeting breaking the sound barrier causes as the bullet goes supersonic.ĭownrange, as the bullet goes subsonic, it gets jostled around again, but nowhere near as bad. Generally the bullet goes supersonic while it's still in the muzzle. Then you work up your load so that it either stays above sonic or below sonic from the muzzle to the target. (speaking of handguns other than a rimfire and handloads)Īhhh! That's where the rub & the fun comes in.įor best results you want to take an educated guess as to what your max range is going to be. 22's, it just about any ammunition that's more accurate if it stays on one side or the other of sonic.
0 kommentar(er)
