My 260 barrel went 4068 rounds, right before it starting grouping like a shotgun I was tagging golf balls at 500, a Bartlein 8twist started life with a very short chamber, a 139 Scenar was touching the lands with a Ojive length of 2.150, 41.0 of H4350 in Rem brass sent them out at 2810, after 1500 Scenars I switched to 140Amax .010 off the lands, after 1500 of those, I switched to a jump tolerant 142 SMK, somewhere around 2000 rounds I switched to Win 7-08 brass, or Win 243 brass because in the matches I shoot brass is lost, and 7-08 and 243 Win brass was easier to find and half the cost of Rem 260 brass, and where the Rem brass lasted 5-6 loads and the primer pockets let go, some of my Win brass has 30 loads thru it, at the end it took 45 grains of H4350 to send the 142s @2790
Now I'm having a 8 twist Rock that I won off the prize table chambered in 6.5 Creedmoor, I'm not happy about the reamer specs, I really wanted a tighter neck because I turn necks and little shorter lead, but this barrel was free, as for brass being a single source is no biggie, all the jacka$$ work has been done converting 243 to Creedmoor, check out TRENT over at http://www.65creedmoor.com/ on how. The 30 degree shoulder is the reason I'm switching, I didn't find my 260 hard to load for, but I want 6.5 short action mag round round with room to grow, and cheap brass.