338 Norma Improved.

[Rhovee]

Here is some info I have for 338 NMI.
I am using:
24" barrel
Lapua brass
CCI 250's
300 grain EH Berger's
Built by Alex Wheeler
Fire formed with 300's +.015 in the lands with
85 grains H1000.
I started with H1000 and have excellent accuracy at typical non improved speeds. Ran up to 2830 before bolt click. Shot best at 2720 with 1" at 300 yard groups. Had one 3/4" group.

Then I tested some N570. Never did hit pressure, case gets to full. At 94.5 I can feel a slight crunch with powder while using 6" drop tube. Attached is a picture of a seating depth test I did tonight. There is some good consistency with accuracy and velocity in these groups. Total of .015 seating depth and all shot well. All shots had an Es of 20 and I might try Fed 215 and see if that changes. If not I will wait and shoot it at 1k and see what works the best.

Powder numbers;
H1000
89.5-2700 (Accuracy)
90-2715
90.5-2744
91-2750
91.5-2785
92-2810
92.5-2810

N570
91-2690
91.5-2704
92-2730
92.5-2759
93-2775
93.5 2772
94-2800 (accuracy)
94.5-2820 (accuracy)

Figured someone would be needing this info

 

[snox801]

I like that round. Might be worth giving rl33 a try most my large capacities like that but the 24" tube may be a bit to short with that powder.