I'm sure you would exceed 1300fps mark with 5" LW barrel / 12gr N105 / magnum primers / warm summer day, but I'm not sure it's still safe. Be sure your barrel is shiny clean before you start to chrono each of this 10 round batch. And maybe you should rise with max 0.2gr steps, not 0.3gr, but it's your gun and the rest behind it as well.
One of CCI350's advantage over CCI300's is less powder and less compression so the hollow point remains ok. Anyway, 12gr N105 and 180gr XTP makes some powder compression at 1.260 OAL but N105 takes it good.
Please let us know about results as soon as you can.
Better be judged by twelve than carried by six.
Last edited by robert91922; 07-18-2011 at 11:59..