I have shot an unreal number of thousands of p. dogs with the 223 and 6ppc. I made the 6ppc brass from 7.62x39 brass with the large rifle primer, still shot bug holes inspite of what you hear.
P. dog, ground squirrel, and jack rabbit rifles, hard hot shooting.
Barrel life is much better with the 6 ppc than the 223. I found that when benchrest barrels were shot out to where the bullets would have to jump, they would still shoot in the 2's with 55-65g bullets with good accrobatics on animial pests destroying pastures and hay crops. I shot a fast lot of 2230-S, which is H335. I cleaned every 300 rounds with both the 223 shooting 748 and the 6ppc with 2230-S.
When I changed powders in the 223 to AA2015, H322, my cleaning frequency became every 150 rounds, like wise in the 6 ppc as the powder fouling with these powders were starting to form a carbon ring that was tough to get out. Our shooting was hot and fast with both cases.WARNING: N133 and 135 eats barrels like you are shooting battery acid.
I shot the 6ppc so hot I was worried about the panda action coming unglued from the bedding in the stock.
For a guy that is wanting to shoot an informal target rifle or a super accurate colony varmint rifle, a Remington 700 with the bolt face bushed and sako extractor installed, MHV barrel, 28", good heavy laminate stock, put on a muzzle break, and you will have one of the most accurate and enjoyable rifles you could imagine. I would go with a 12 twist with about .035-.045 freebore MAX, and you may not live long enough to shoot the barrel out if you shoot H335 with bullet weights up to 75g Vmax.
A favorite of mine is to start off with Zero freebore with a 55g Nosler, 55g Sierra blitz king, 60g Sierra or Berger at 3650 fps shooting bug holes over a wide range of powder charges.
12T for the 69g Bergers will carry the freight way out there with the zero freebore.
NOTE: the only 7.62x39 brass that is tough enough to take PPC pressures is Lapua and PMC. PMC has not been available for a long time. So, with the 6ppc, you are limited to small rifle primer brass, and use a very hot primer with H335.
With the Stolle Panda Right bolt, left port, I would shoot up to 6 dogs per minute, sustained fire till I could not see through the scope from barrel heat. The throat on this rifle was set up for the 68g berger, so it was on the longer side. I shot this 14T Hart barrel for almost exactly for 10K rounds. At 8000 hard rounds, it was still agging in the mid 2's with 60g benchrest bullets that I made. I decided that the barrel was gettting a bit hard to clean, so I did a test to see if the barrel would take 600 shot strings. These long strings put a quick end to the barrel being easy to clean, still grouping in the 3s, but a bitch to get the copper out of.
I had a new 28" unturned blank put on with a zero freebore reamer. Everyday is a great day when I pull that rifle out and shoot it with the PMC brass, H335, and 60g bullets.
Head shooting p. dogs at 300 is not such a big deal with the 6 PPC. My p. dog hunting partner went with the 6 BR shooting the 60g at 3700. His rifle performed about as well as my panda 6 PPC, he used H335 also cleaning every 300 rounds.
It will be much easier on a guy to go with a 6 BR vs a 6PPC, but the BR is not quite as easy to tune, nor is the tune range as wide. It would be very practical for a guy to go with a 6 BR vs a 6 PPC if he were not already set up for a 6 ppc.,,never look back.