On 15 Sept/09, I made loads for the CZ550 using the 500gr Hornady RN from six powders: 83 grs748, 78 grs H335, 80 grs AA 2460, 78 grs 4320, 78 grs Varget and 76 grs IMR4064.
The 78 grs 4320 gave 2165 fps (corrected to MV) with this note: "Not max." (Compared to Barnes data)
COL for all was 3.34".
The 78 grs of Varget gave 2158 fps (corrected to MV); 78 of H335 = 2204 and 80 of 2460 = 2206 (each corrected to MV). 83 grs of 748 was a big disappointment at 2076; 76grs of IMR4064 = 2108 fps corrected to MV - that was not max in MV but in compression. I did 79 grs H4895 later on Jan 7/10and got 2266 ( -7 *C) AA2230 wasn't available in this neck of the woods at the time.
The CZ had a 25" barrel. Just some history from my experience.
