So tomorrow couldn't wait. When you have a silencer and a flashlight the test range is always open.
What I did is place a powder-coated, split nose bullet in a vee-block and drill a 1/8" hole through the bullet nose right at the end of the foil at the end closest to the base. That puts it about 1/4" from the front band. That's SIDEWAYS, Freebullet, not through the point in the usual, lengthwise fashion.
This seemed to start expanding in the carpet, and blew a very satisfying hole through the stack of cardboard. Examining each layer closely, it appears that the bullet grew two "wings" as it went through, and after 3-4" the cavity damage in the cardboard pack was starting to grow considerably The exit hole was about .45 caliber but the cardboard was shredded fiber mush radiating nearly an inch all around, indicating what I think is shock energy dump. The bullet did not come apart. I used the long end of a power pole as a backstop and the bullet base is at least three inches inside the pole, with shredded cardboard fragments and shredded wood all around the hole.
So I think this will work, combining the foil strip for an almost-split nose with intact tip, and drilling a hole through the side of the nose right through the parting lines at the back end of the strip. Believe me, it made me a little nervous putting one of these abortions through my silencer, but no harm done this one time anyway, and the hole wasn't perfectly centered. These may not group well if I can't keep the bit from walking.
The Lee mould's alignment pin locations prevent me from cross-drilling the mould for a sideways "hollow point" pin, but I wonder if it wouldn't be possible to drill through the sides of the mould and install slightly tapered half-pins in each side to cast the crush zone in place. Maybe even a crush zone that's more effective than a drilled hole if the tip of the half-pins were filed to a teardrop shape....