windsage Wrote:My Hornady brass measured .0125" thick at the neck before forming. After I necked them down They measured .014". The neck in the chamber is .255" but I still got higher than expected pressures. When I checked the fired cases, some of the necks had gotten thicker as they fired. and were showing .254" OD and .222" ID. So, I am going to neck turn them and try again.
The shoulder on the .224 Predator appears to be exactly where the 6.5 Grendel shoulder was. Since the shoulder taper now goes to .224" the actual neck is slightly shorter. You can hold them side by wide with the 6.5's and see the difference.
The most common powder seems to be CFE223 and it's only filling the case about 90-95% with the 75gr ELD. I bought some 95gr SMK on sale, and hope to try them to see if they like slower powders. Just doing some Quickload estimates, it looks like we get close to H4350, RL16 or RL17 territory with the 95's. With those I can make real use of the larger volume. My goal is to get the 95gr to 2800 fps. This would closely mirror the trajectory of the 6.5 Creedmoor.
The 22PPC brass has thinner necks than Hornady, with Hornady brass loaded i am at .2515 , PPC .248 which would not require turning for your chamber.
Imagine annealing often would be the ticket with the added working of the neck.
The 22 PPC Also adds .4- .5 gr more H2O capacity vs Hornady.
Word of caution on the 22 PPC brass, because of thinner neck a smaller bushing will be needed to maintian proper neck tension on bullet and the flash hole in Norma brass is smaller diameter than Grendel brass like Lapua brass , both requiring smaller decapping pin.
But like the Hornady brass (just checked) the Norma PPC brass does not fully form to chamber on initial fireforming (which is normal) after couple firings the Hornady is at 36.1 gr H2O and the Norma is at 36.8 gr. After a second firing and may increase a little more with more firings/completely forming to chamber. This gives me a loaded case capacity (Norma brass at current capacity) .5 gr more than a 22 BR with a 53 gr bullet @ my aol vs Nosler 22 BR data.