I have shot handguns for years and years but just recently started reloading for the 45 Colt. I have 3 firearms chambered for it and enjoy everyone of them. The first one I bought was a Ruger 45 Convertible (45ACP & 45 Colt) the next a Puma rifle and the third a M25 -7.
I have several bullets I cast for 45ACP and one especially for the 45AR for use in my M625JM. That bullet is an H&G #502, 240gr LSWC of the Keith design. Now I have a Mihec mould that is a copy of the RCBS 45-270-SAA that weighs in at 285gr as a solid and 270gr with the round hollow point pins.
When the latter bullet was shot from the Ruger, loaded to Brian Pearce's data for 30,000psi loads, I could adjust the sights for it to hit POA/POI. The rear site had to be moved down. That means that the bullet was hitting higher. Now, that bullet was traveling somewhere near the 1300fps mark. The previous loads that I ran from this firearm was the above mentioned 240gr bullet with a similar velocity, maybe a little faster, 1400fps.
Then I got the Smith. Now, I believe that it will take the above mentioned loads BUT am just a chicken to try at this time. It is a super nice gun and I don't want to ruin it before I even get started, so to speak. At any rate, I started off with a load of 9.0gr of Unique, well within published data, under the 240gr H&G and found that even at 25 yards that it was printing about 6" high! Velocity was near 950fps, as I recall. As I tried to adjust the sights to compensate for this, I ran out of adjustment room. Printing high means that the rear sight has to move down to get POA to equal POI.
I "adjusted" the rear sight with a file to lower its overall height and then deepened the groove in it to allow me to see the full front sight then re-blued it. Now it hits where I aim it with the 950fps 240gr load as I mentioned above. I do not need to shoot it to know two things.
#1: If I were to take my 45-270-SAA bullet and load it to the same velocity, it will print higher on the target, period.
#2: If I were to take my H&G #68, 200gr LSWC and load it to the same velocity it will print lower on the target, period.
Both statements assume two things.
#1: Point of aim is the same.
#2: The distance to the target is the same.
Barrel dwell time is a big factor in shooting handguns, no doubt about that. While I haven't spent a lot of time doing ladder test targets, I have proven the above statements over and over and over again, in more than just this one caliber.
What happens when you hot rod the 270gr bullet to "infinity and beyond"? Where will it print on the target? There are two many factors to put into this equation to say too much for certain BUT, I can tell you where it will hit if I am shooting it, higher. Take the 200gr and do likewise, load it to "infinity and beyond" and it will still print lower than the 270gr at slower typical velocities.
Why? You can figure that one out, I really don't need to KNOW the why of it. If I want to be the reloader/handloader/shooter that I want to be, I sure had better know that this is how it works in real life!
Otherwise, I am going to have to spout INTERNET theories and "ought to be's".