As you start talking about the 6.5PRC make sure you play with the numbers to make sure you haven't left your original goal behind. Also if you're a 1 gun guy that isn't ideal for practice (just go get a second gun btw 
).
Monos you don't go long/heavy but in my opinion don't go the lightest either because you tend to loose out due to loss of BC sooner than later (play with the numbers in specific cases). In 7mms I tend to shoot monos in the 130-145gr range for instance.
Skip the 280rem, 6.5-06 type options unless you plan to replace the bottom metal for something that handles a longer COAL. If you ever want to hunt CO (or some other places) don't hang your hat on 223 as an option at the moment (but you might as well get one for practice ).
I usually hunt monos and the kids currently use a 243win with the 80ttsx (its a 10 twist), I'd like to eventually spin up a faster twist 6creed. But if I'm honest I am leery about them using the 243win on larger game at longer ranges with the 80ttsx because like you I'm worried about less wound channel from the mono. That said it's dropped deer and antelope well to date out to 350yd. Haven't played with DRT or the Cayuga which could be options I try in the future.
I pulled the barrel off a 7-08 and put on a 19" 284win this year because I didn't want to loose so much velocity while going with a shorter barrel. No kills get with it but the 131hammer is still 2150-2200fps out at 500yd at my altitude. I couldn't get the 139LRX to group well in my initial load work so far. With a suppressor I don't loose sight picture shooting prone but that is prone which is easier to manage.
BTW I don't have the answer for you because I have multiple tikka actions things that appeal to me range, 6creed, 6-284, 284win as I've got. I have various 6 and 7mm so I am trying not to be tempted by 257creed, 257-284, 6.5-284... but you can be tempted all you want.
).Monos you don't go long/heavy but in my opinion don't go the lightest either because you tend to loose out due to loss of BC sooner than later (play with the numbers in specific cases). In 7mms I tend to shoot monos in the 130-145gr range for instance.
Skip the 280rem, 6.5-06 type options unless you plan to replace the bottom metal for something that handles a longer COAL. If you ever want to hunt CO (or some other places) don't hang your hat on 223 as an option at the moment (but you might as well get one for practice
).I usually hunt monos and the kids currently use a 243win with the 80ttsx (its a 10 twist), I'd like to eventually spin up a faster twist 6creed. But if I'm honest I am leery about them using the 243win on larger game at longer ranges with the 80ttsx because like you I'm worried about less wound channel from the mono. That said it's dropped deer and antelope well to date out to 350yd. Haven't played with DRT or the Cayuga which could be options I try in the future.
I pulled the barrel off a 7-08 and put on a 19" 284win this year because I didn't want to loose so much velocity while going with a shorter barrel. No kills get with it but the 131hammer is still 2150-2200fps out at 500yd at my altitude. I couldn't get the 139LRX to group well in my initial load work so far. With a suppressor I don't loose sight picture shooting prone but that is prone which is easier to manage.
BTW I don't have the answer for you because I have multiple tikka actions things that appeal to me range, 6creed, 6-284, 284win as I've got. I have various 6 and 7mm so I am trying not to be tempted by 257creed, 257-284, 6.5-284... but you can be tempted all you want.
