For longer range shooting, you really want 1500 fps, and a bit more if you can get it.
I'm having Steve Zihn build me a .62 Rigby style '
cussin' gun, but it is still over a year out in the queue. He is putting on a 2-leaf ghost ring sight, specified for 75 and 150 yards. With a hunting load of 120-150 FF, that should give me a point-blank range of 175. The .62 in fact shoots flatter than the smaller bores
at the same velocity. You just pay for it with more recoil. I'm spec'ing my gun out to weigh 9 lbs. I probably should have gone swamped, but I specified straight taper 34". With an English sporter stock cut to my dimensions, I don't anticipate recoil will be a problem.
I have a 16-bore (.66) Christian Springs w/ a 38" swamped Forsythe-rifled Ed Rayl barrel, and it is a tack driver. I didn't order it, I bought it from the man who did. Steve sighted it in for 75 yards w/ 150 gr FF, and it does alert you to the fact that you have pulled the trigger. But it doesn't "hurt". I have no problems shooting it 20-30 shots in a day practicing, and my shoulder is not sore the next day.
I have a .72 Pedersoli Gibbs African that is comfortable to shoot w/ 120gr FFg and a 540 gr. .710" PRB. 20-40 shots a day and my shoulder does not hurt - not even the next day. The trajectory past 75 yards does get a bit loopy, but that is because I do not like shooting the 140-160 gr. of FF it would take to flatten it out. The accuracy (and power) are certainly there. It is WAY cool for knocking down dead trees. :grin:
The British tended to 10-8 bores in Africa, and 16-14 bores in India. A Forsythe rifled PRB gun in those ranges will handle ANYTHING they are likely to meet. I love my 16-bore, but a 20-bore will do the same for North America.
http://i1219.photobucket.com/albums/dd439/alan_atwood1/cs08.jpg