FPE really means nothing in killing power of round balls - and most everything else for that matter. for example:
: I have witnessed a .54 round ball, started at (for it) a measley 1,600 to 1,700fps, only 100 gr. Pyrodex, kill a big bull moose at a lazered 170 yards. Impact fpe might have been in the 270 to 300 range. The ball broke a rib going in, first lung, centred the heart, off lung, and was under the hide of the off side. The moose bolted at the shot wihtout sign of being hit, but dropped within 40 yards of where it was standing when shot.
: Those who like big numbers, like to think it takes 1,500fpe impact energy to kill a moose, and 1,000 for deer. The above noted 235gr. ball had neither and perhaps a 1/3 of what is supposed to be needed for deer. This should show how much faith should be put in numbers which reward high velocity only, but tell nothing of what a particular projectile is capable of.
: My close friend and hunting buddy, with his "Purdey styled" .75 rifle, had to drop his hunting load from 200gr. all the way down to 120gr. of 2F, just to keep a .735" round ball inside a moose. For the first 4 years he used it, he couldn't keep a ball inside. He merely wanted to recover the balls as records of his moose, something he does with his modern rifles. Bull moose here run in the 900 to 1,300lb. range, with the odd giant of 1,500lbs., considerably larger than the Shiras moose, common in some areas.
: I prefer to have a large round ball travelling 1,500 to 1,500fps to obtain a reasonably flat point blank range to 1000yds. where the ball is not more than 1 1/2" above nor below the line of sight. A 14 bore, with .684" ball of 484gr., will give such a point blank range to 120yds with 165gr. 2F GOEX BP. To have that flat trajectory with a large ball, is a wonderful thing. Having the ball within 1 1/2" of the Line of sight to 120yds. makes pin point accuracy a normal & easily aquired result. With the large bore, accuracy merely improves, the more powder used and the trajectory becomes flatter, rather than giving any expra elevation to the ball. The sights must be low, on the barrel for this longer range Point blank sight to work properly. High sights merely add elevation to the ball with more powder, destroying it's point blank range. Light loads and attendent low velocity also destroy the point blank range, due to required high elevation at say, 50yd. to hit the mark at 100.
: When a 14 bore or larger ball strikes a large game animal like a Moose or Elk, the animal shudders and collapses at the impact. A smaller bore, like a .54, while effective for the same North American game, fails to show hits like this. The animal merely makes a frightened dash. The moose story at the top of this post had the guide thinking the hunter had missed and wanted to get the dogs to track it, yet it lay 40 yds. from where it was standing when shot, just out of sight of the hunters.
: I firmly don't believe in FPE and really feel there is no mathematical formula which describes what a properly placed bullet of ball will do.
: ACCURCY is what is desired, with "Enough Power". The bore rifles have that in spades.