Jim Shockey has used 100 grains of powder and a 300 grain bullet to take every North American game up to and including a polar bear. So yes, in my opinion, the 100 gr pyrodex and a 300 gr shockwave should be adequate.
However, I would personally never hunt an elk with a 295 powerbelt (possibly a 300 gr platinum, but not the 295 aerotip). In general, if you push a powerbelt too hard, or use a bullet below their 348 gr, the bullet has a track record of coming apart on impact. Personally, when I hunted elk with a powerbelt, I shot the 405 gr. and 95 gr. 777.
Comparing a 300 gr sabot to a 295 grain powerbelt is comparing apples and oranges. The sabots are generally build stronger to hold up to higher velocity impacts.
That said, aren't you hunting Colorado, at least for elk, where sabots are not legal?
If I were hunting elk and deer in Colorado (which I am) and expected some long shots on timberline bucks (which I am), then I would use the Hornady FPB (which I am)
After another good shooting session with my Omega and FPB's today, and thinking about the stuff I have read about how tough the FPB's should be, I am more and more thinking this is the ideal Colorado conical. That is of course, if you remove or cut off the tip so it is legal to use in Colorado.
txhunter58
venor, ergo sum (I hunt, therefore I am)