It it bad form to resurrect such an old thread, but the idea of using a jackhammer was posed and no one appeared to have followed though.
It does work!
I used a cheap ($125) 35lb electric breaker (it's red and can be seen in one of the pics) on some LARGE red oak rounds.
Other options were to use the wedges, maul, noodle or man-handle onto the splitter.
The jackhammer seemed like a better than moving the rounds again.
Standing on the round, still in the trailer, I position the bit inline with natural splits or with the grain.
If it appeared the round was not going to split, I'd re-position the bit before it got stuck.
The bit did get stuck once and I just pulled the jackhammer off the bit and put another on to finish the split very much like using a second wedge. (I've ordered 2 more bits. They are cheap.)
The jackhammer allowed me to knock these big rounds down to a manageable size that i will finish splitting with the splitter.
As for knots, not so much. But for straight grain stuff, yes, yes yes!
(re-posted of the same pics "
Scrounging firewood" thread)