I can relate to your concerns about COL
(Cartridge Overall Length) vs. volume of the case below the base of the bullet. I feel, though, that unless you are into the realm of rifle bench rest shooting or 1000 yard matches or long range varmint shooting, the volume concerns are pretty insignificant. If you can find ANY published information as to COL with that bullet, I bet it will be safe. There has to have been at least a certain amount of R&D work done. My rule of thumb is,
If the loaded cartridge LOOKS grotesquely short or long, it probably is not right.
The lengths you list are pretty close to what my manuals show as proper. 1.250 to 1.265 with a 230 RN is just about right.
I'd say load the 200 plated round nose bullets to nearly same COL as with the 230 RN. Only difference would be is there was insufficient bullet inside the case for secure holding. The general guide is to have the bullet seated inside the case to a depth of at least one-half the bullet diameter. So, with a .452 bullet, you need at least .226" inside the case mouth.
With the 225 FP, try 1.200 COL. I bet that will work. Speer illustrates a 200 JHP with a somewhat rounded nose, but it is still pretty broad, with a COL of 1.155". You might have to work with this length somewhat.
Generally, the longer, narrow nosed bullets can be loaded SLIGHTLY longer than those with broad meplats, due to the forward curve of the magazine. Max COL listed in Speer is 1.275, and this is shown only with the long, narrow-nosed semiwadcutter bullets, like the H&G 68 bullet. And many, like Brother Bowman, find it works better to seat even these as much as .025 shorter.
BTW--The H&G 68 200 gr. was designed, I read, to work well through the old style NON-throated barrels. A line drawn between the edge of the meplat and the shoulder of the bullet pretty well duplicates the similar points of the 230 hardball bullet. For this reason, I find it works quite well to leave my seating die set for the 230 RN when I load the #68-style bullet. Functioning in several 1911 pistols is flawless. I even leave the powder measuge set the same. The lighter bullet with same powder is beautifully accurate.
I think you'd be much better served to do as the other responders suggest--set the bullet in the case for reliable feeding, and forget the case volume. The differing weight bullets will have far greater effect than the timy difference in case volume.
The above remarks apply only when using standard charge weights. With max loads, seating a bullet even slightly too DEEPLY may result in dangerously high pressures. But, we were speaking of altering volumes with bullets seated rather longer than shorter.
Best of luck in your efforts.
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[This message has been edited by Johnny Guest (edited September 02, 2000).]