I ran a bunch of 5 round groups through the chrono over the weekend.
Barrel: John Benjamin 18" fluted with .264 LBC chamber (uses 7.62X39 bolt)
Elevation was 2700'
Temp was 58 deg
Hornady 2x fired brass
Sierra 107 SMK
2.260 COL
No crimp
Cases were sized using the rcbs 16407 Small base die
H335 (5 shots of each charge)
charge High Low Ave ES SD
27.3 2407 2366 2390 41 14
27.6 2443 2383 2417 60 20
27.9 2462 2427 2450 35 12
28.2 2511 2466 2492 45 15
28.5 No data (chrony was not ready)
28.8 2576 2543 2559 33 14
29.1 2609 2578 2596 31 12
29.4 2629 2607 2615 22 8
29.7 2640 2630 2636 10 3
30.0 2672 2647 2658 25 8
Accuracy was good from 29.1 up to 30 with the H335. No pressure signs. I will get more granular in the 29.7 range and go a little above the 30g published load.
8208 (5 shots with each charge)
charge High Low Ave ES SD
28.6 2518 2488 2503 30 12
28.9 2549 2528 2538 21 9
29.2 2586 2545 2562 41 14 Slightly compressed
29.5 2609 2569 2586 40 14 Compressed
29.8 2636 2601 2620 35 11 Very compressed, seating die puts light ring around nose of bullet
Starting with 29.2 I settled the powder in the brass before seating. COL did not grow overnight on any of the compressed loads.
Best accuracy was with 29.8. This was the best group of the day.
I also bought 2 boxes of Hornady 123g ELD-M ammo. Here is the chrono data for 5 rounds:
H: 2395 L: 2385 Ave: 2388 ES: 12 SD 4
The accuracy of the ELD-M factory ammo was not impressive in my rifle but I want to re-test on a more stable shooting platform. I'll bring my sand bags with me next time.
Barrel: John Benjamin 18" fluted with .264 LBC chamber (uses 7.62X39 bolt)
Elevation was 2700'
Temp was 58 deg
Hornady 2x fired brass
Sierra 107 SMK
2.260 COL
No crimp
Cases were sized using the rcbs 16407 Small base die
H335 (5 shots of each charge)
charge High Low Ave ES SD
27.3 2407 2366 2390 41 14
27.6 2443 2383 2417 60 20
27.9 2462 2427 2450 35 12
28.2 2511 2466 2492 45 15
28.5 No data (chrony was not ready)
28.8 2576 2543 2559 33 14
29.1 2609 2578 2596 31 12
29.4 2629 2607 2615 22 8
29.7 2640 2630 2636 10 3
30.0 2672 2647 2658 25 8
Accuracy was good from 29.1 up to 30 with the H335. No pressure signs. I will get more granular in the 29.7 range and go a little above the 30g published load.
8208 (5 shots with each charge)
charge High Low Ave ES SD
28.6 2518 2488 2503 30 12
28.9 2549 2528 2538 21 9
29.2 2586 2545 2562 41 14 Slightly compressed
29.5 2609 2569 2586 40 14 Compressed
29.8 2636 2601 2620 35 11 Very compressed, seating die puts light ring around nose of bullet
Starting with 29.2 I settled the powder in the brass before seating. COL did not grow overnight on any of the compressed loads.
Best accuracy was with 29.8. This was the best group of the day.
I also bought 2 boxes of Hornady 123g ELD-M ammo. Here is the chrono data for 5 rounds:
H: 2395 L: 2385 Ave: 2388 ES: 12 SD 4
The accuracy of the ELD-M factory ammo was not impressive in my rifle but I want to re-test on a more stable shooting platform. I'll bring my sand bags with me next time.
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