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Discussion Starter · #1 ·
So after researching the forum for days I decided to run a ladder with H322 and the 105 MKZ in both new primed S&B brass and new star line brass with REM 7.5 primers.
Both new cases were run through neck sizing mandrel to true necks. Did not FL size.

I ran pressure testing varying .in 3g increments starting at 28.2g running up to 30.0g
COAL - 2.295 for both cases.

temp-65; sea level
16” ARP scout 1:11.25 5R
Chrono- Caldwell
distance to chrono; 10 ft
target distance - 100 yards

S&B New brass
28.2-2523
28.5-2527
28.8-2562
29.1-2572
29.4-2598
29.7-2596
30.0-2633

New Starline brass
28.2-2508
28.5-2528
28.8-2555
29.1-2576
29.4-2616
29.7-2627

Stopped here and should have loaded more, as no pressure signs were evident on any cases. I will run another ladder starting at 29.7 and go up to 30.5 to see what my limits are....If I can compress the powder enough to get 2.295 COAL.
Curious result with the starline as the entire ladder grouped into 1.2 MOA, with 6 of those shots falling into 1MOA. Not certain where to go with that....wishing I had a longer distance to shoot, but I have to take what I can get.

69369

For the record, I do have AA2200 but my rifle just doesn’t seem to digest it well. The best I’ve been able to achieve with 2200 and this rifle is 1.5 MOA. Appears that H322 may be what it likes to eat, even at the sacrifice of a little speed. If I can get the 105’s to group well at 2700 I’ll be happy!
 

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Thanks for the info. I don’t have the S&B brass (hoping to pick some up when available) but I have some 105 and 120 MKZ’s that I will be loading with A2200 and H322 and Starline brass soon. Curious to see how the different powders perform


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Did you crimp these? What was the dope from the 30.0 gr Starline Brass? Or did you not do that one?
 

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Discussion Starter · #6 ·
Did you crimp these? What was the dope from the 30.0 gr Starline Brass? Or did you not do that one?
Yes, medium crimp with a Lee FCD. I didn’t load a 30g load in starline, but will continue the pressure testing starting at 29.7 and work up to 30.5 on my next range session. I’ll try to keep coal at 2.295, but I may have to go 2.30 in order to seat the bullet on the compressed charge. It started to compress at 29g In starline brass.
 

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Discussion Starter · #7 ·
Thanks for the info. I don’t have the S&B brass (hoping to pick some up when available) but I have some 105 and 120 MKZ’s that I will be loading with A2200 and H322 and Starline brass soon. Curious to see how the different powders perform


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I haven’t run the 120s in starline brass yet, but with new S&B brass with H322, the groups were sub MOA at 2.295, Charge weight was 27.6-27.8g. Average velocity was 2415
 

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Discussion Starter · #8 ·
Follow up with additional testing. Same basic data as original post with the temperature now at 82. New Starline brass at the following charges with a COAL of 2.297

Resuming pressure testing starting at 29.9g H322
29.9g-2630
30.2g-2610
30.5G-2671

light swipes on one case at 30.2 and one at 30.5 but no flattened primers. I stopped here. No reason to continue. Case volume is lacking and I had to vibrate the cases

Groups:
3 shot each at 29.9, 30.1, and 30.3. Same Coal at 2.297

29.1- 2620 average at 1.06 MOA
30.1 - 2623 average at 0.747 MOA
30.3 - 2640 average at 0.726 MOA.

No pressure signs; light shine on 30.3 case heads but no true swiping. Primers were fine. Ejection at 3oclock.
 
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