2nd Round Update (supplement to earlier post - my first post on 4/11 above) - - - Got to the range again today (65 degrees f) and here are the results with a 26" Krieger barreled AR-15 upper, 1:8" twist, .236" x .243" , with naked Berger 108's loaded magazine length (i.e. 2.260" OAL), using fire formed and re-sized AA Arms (Lapua) brass, BR-4 primers and CFE 223 Hodgdon powder (with all thrown charges, not individually weighed) all magazine fed:
31 gr. CFE223 - 2792 MV, ES 19, SD 7
32 gr. CFE223 - 2867 MV, ES 14, SD 6
There were no pressure issues and another .5 to 1.0 gr of powder is likely workable pressure wise up to 2900 fps.
FYI - - Here are some other loads chronoed at the same session today with the Berger 108's magazine length and mag fed with everything else as noted above:
29 gr. H335 - 2756 MV, ES 24, SD 9
30 gr. H335 - 2836 MV, ES 14, SD 5
32 gr. 2000-MR - 2811 MV, ES 17, SD 6
32.5 gr. 2000-MR - 2869 MV, ES 29, SD 10
No noticeable pressure signs, may go another .5 to 1.0 gr higher pressure wise probably in the 2900 fps range
28 gr. 8208XBR - 2711 MV, ES 13, SD 5
29 gr. 8208XBR - 2793 MV, ES 33, SD 12
28 gr. H4895 - 2708 MV, ES 27, SD 9
29 gr. H4895 - 2806 MV, ES 9, SD 3
Robert
AR-X Enterprises, LLC
www.6mmAR.com