And...since nobody else has posted any negative comments, I guess I'll be the villain here...
Hey, gotta have villains.
... First and foremost is the higher pressures involved with heavier than normal boolits and reduced case capacity...
Not necessarily true. For a given weight, cast bullets occupy less volume than a "normal" bullet for the .45 ACP, as a "normal" bullet for the .45 is jacketed, and lead is denser (takes up less room) than copper. Remember, a bump up in weight from 230 gr. to 250 gr represents a change of only 8%.
While I'm on the topic of jacketed bullets, I should point out that all else being equal, jacketed bullets yield higher pressures, owing to their increased hardness. The worst offenders are JHPs, as not only are they harder, but the sizeable hollow cavity makes it necessary to seat more of the bullet's volume into the case.
Poor crimp and/or poor case neck tension can allow the boolit to telescope deeper into the case when it hits the feed ramp. This reduces the case capacity by a significant ammount and can cause dangerous pressure.
This is true of any bullet.
The more abrupt ogive of the RNFP boolit compared to the traditional RN profile often requires that the RNFP be seated much deeper in the case than the RN which further reduces the available powder space...
Not necessarily true. As you point out, a RNFP bullet has a more abrupt ogive, and when loaded to a length that makes the same contact on the feedramp as hardball, frequently has a greater proportion of its weight outside the case.
The deep seated heavy boolit can protrude into the thicker part of the case and cause a bulge at the base of the boolit that can interfere with chambering. This could possibly lead to a situation that will allow the cartridge to chamber, but not have enough clearance for the brass to expand and release the boolit, leading to excess pressure.
Um... no. Either the round will chamber, or it won't. If it chambers, there will be sufficient clearance. Now, we could get into a discussion about varying chamber dimensions (volumes), but that's a whole 'nuther discussion.
There was a trend in IPSC competition for a few years toward heavy for caliber boolits and I have witnessed all of the problems described here in 45 ACP and in 40S&W. The lack of catastrophic failures and personal injuries reported with these loads is a testament to the strength and durability of John Browning's 1911.
Or, the lack of catastrophic failures and personal injuries reported with these loads is testament to the fact that loading boolits a few grains over "standard" makes little or no difference. And whether or not you believe JMB's 1911 is as strong as some of the other popular designs out there (it's not), is a debate that could fill many threads of its own.
I have fired many thousands of 260 gr. RNFP's in 45 ACP. I can't claim that I had no problems...there is a learning curve...
That's true of just about any aspect of reloading...