I've got a custom .260 that I built up on a Rem 700, that with 123 and 142gn SMK's will group 1/2 moa consistently.
My question is, what is the realistic max hunting range of this calibre?, when used on deer sized game? The numbers I have run tel me that the 142's hold 1000ftlbs out to around 600yds. With sufficient accuracy to group inside 6" (vital zone)at this range, I summise that 600yds would be the max for this cartridge.
With those bullets I'd probably asy that 600yds was a stretch ,the only reason being that the SMK's are built pretty stout and I doubt that you would get good expansion at that range.
Now move to a 140gr Berger or A-max that has a alot thinner jacket and softer lead for the core and the 260 is a 1000yd deer rifle ,I took my longest ever deer this past season at 944yds with a 140gr Berger.
+1 on the 140 amax.- The berger has a higher BC but in my experience terminal ballistics are not so impressive as the Amax. I have more experience with the latter, shooting out of a 6,5 x 284, so I am not saying the Berger does not work. In fact I´ve switched to see if I can strech my distances with the higher BC.....
It is doing 1/2 moa field shooting, and off the bench will do a smidge better (around .4)
Thanks for the advice, looks like it could be a 3.5-10 going on it. The country we hunt here is very rugged, and involves a lot of climbing so I don't want to make the rifle too difficult to carry. As it is my only rifle, it also gets used for quick close range offhand shooting too, so balance is a consideration also.
If your gun will hold .5MOA at 1000yds with either the 140 A-max or 140gr Berger then I would not hesitate shooting deer up to the 250lb range out to 1000yds with the 260.
Due to the Sierra Match Kings strounger desgine I would not shoot mid size game any farther than 60yyds because I don't think the bullet will expand reliably at speeds much slower than that.