as others have mentioned there are two areas to consider- the case volume (where is the base of the bullet) and the OAL. When you change from one bullet type to another you need to consider these two things..
for powder charge/weight, the base of the bullet is what is of concern. If you put them at the same OAL, the round nose base will be quite a bit further away from the powder and have a lot more case capacity.
I would do as other suggest and figure out roughly where the base is on your standard loads with the round nose and duplicate that with the flat nose. Figure out your overall length and then work up your powder (start a bit lower) to see where you get in relation to your round nose load.
I know for rifle rounds you can get the Hornady Bullet comparator that measures off the ogive, but not sure if I've seen anything similar for pistol rounds?
for powder charge/weight, the base of the bullet is what is of concern. If you put them at the same OAL, the round nose base will be quite a bit further away from the powder and have a lot more case capacity.
I would do as other suggest and figure out roughly where the base is on your standard loads with the round nose and duplicate that with the flat nose. Figure out your overall length and then work up your powder (start a bit lower) to see where you get in relation to your round nose load.
I know for rifle rounds you can get the Hornady Bullet comparator that measures off the ogive, but not sure if I've seen anything similar for pistol rounds?
