Hi all,
Appreciate all the feedback. I just wanted to give one last update. I was able to spend a whole afternoon at the range shooting multiple load ladders of CFE 223 for multiple .308Win weight/style bullets thru my T/C Compass (22" barrel, 1:12 5R rifling). I chrono'd everything I could (got a few errors and forgot to start capturing data on a few strings). In summary, this is what I discovered:
In nearly all cases, I was able to achieve the target MV at a lower powder charge than listed in either Hornady or Hodgdon load data. Using the max Hornady MV as a target, I started low and increased in 0.5gr increments until I approached the higher charges. I saw the primers start to flatten midway thru the ladder and get progressively worse near max. At max charges the firing pin dent looked slightly cratered (it could be felt with a fingernail). Ejector marks/swipes start to appear 1 or 2 steps down from max MV. At the point when MV reached max I would see ejector swipe marks and in some cases had extraction problems (bolt would unlock but not open). The extraction problems were always at or slightly above Hornady max MV. There was no way I could reach Hodgdon's listed max MV or charge without locking the bolt. Max charge was closer to Hornady data but always less than the listed load. I would even go far as to say that using the Hodgdon starting data could be dangerous (see 150gr FMJ NOTES below). If the suggested starting load was not less than 90% of the max load, I started below the suggested starting load.
Primary reloading guide is Hornady 9th Edition, Hodgdon website tables used where a specific bullet weight wasn't listed in Hornady Hornady loads were always less than Hodgdon and in some cases there was no overlap in the load data. Target MV was the MAX velocity listed in Hornady, or if I had a similar weight factory boxed round, the MV listed on the box. All MV listed below next to my charges are averages.
CAUTION: The following post includes loading data that may be beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The High Road, nor the staff of THR assume any liability for any damage or injury resulting from use of this information.
Data
Case: once-fired NATO 7.62x51mm LC cases (various years); FL resized and trimmed to 2.005"
(I know the NATO cases have smaller internal volume and this could be the reason for some/most of the readings)
Primer: Winchester WLR (large rifle)
Powder: Hodgdon CFE 223
Chonograph: Caldwell G2 Ballistic Precision Chronograph @15ft
150gr Hornady FMJ-BT
Target FPS = 2800
COAL = 2.700" / Hornady Comparitor = 2.119”
42.5gr (2602fps)
43.1gr (2725fps)
43.6gr (2746fps)
44.0gr (2771fps)
44.5gr (2864fps ave)(2922fps MAX)(flat primer / ejector swipe)
45.0gr! (extraction prob!)
NOTE: The Hodgdon starting charge is 48.4gr. Hodgdon max listed charge is 51.5gr with a MV of only 2974fps. At 87% of that charge I am already seeing rounds hitting that MV. The Hornady max charge is 49.6gr @2800fps. I reached that MV 5gr below that.
165gr Speer SPBT
Target FPS = 2700
COAL = 2.800" / Hornady Comparitor = 2.176”
41.0gr (2413fps)
42.0gr (2533fps)
43.0gr (2538fps)
44.0gr (2605fps)
44.5gr (2657fps / flat primer / light ejector marks)
45.0gr (2715fps / flat-cratered primer / ejector swipe)
NOTE: Hornady lists max charge as 47.2gr @2700fps
178gr Hornady A-Max
Target FPS = 2500
COAL = 2.800" / Comp = 2.167”
38.0gr (2245fps)
39.0gr (2322fps)
40.0gr (2352fps)
41.0gr (2375fps)
42.0gr (2424fps)
42.4gr (2449fps)
42.9gr (2543fps / flat primer / light ejector marks)
43.5gr (2542fps / flat-cratered primer / ejector swipe)
NOTE: Hornady lists max charge as 44.6gr @2500fps
208gr Hornady A-Max
Target FPS = 2470
COAL = 2.810" / Comp = 2.144”
38.0gr (2248fps)
39.0gr (2308fps)
40.0gr (2359fps)
40.8gr (2408fps / flat primer)
41.0gr (2400fps / flat-cratered primer / ejector mark)
41.5gr (2465fps / flat-cratered primer / ejector swipe)
42.0gr! (2484fps / extraction prob)
NOTE: Hodgdon lists max charge as 43.7gr @2474fps
Summary: The above basically illustrates that the Hornady listed MAX MV appears to be the point where elector swipes and problems with extraction happen with my rifle (YMMV). The cratering of the firing pin dent in the (Winchester) primer seems to be a good indicator that I am very close to the max charge. Ejector swipes are the prelude to the bolt getting stuck. None of these reflect the recommended charges vs. MV listed in either Hornady or Hodgdon data.
For me, next steps will be to reproduce some of the charges using .308Win cases (not NATO).
