300 Norma Mag Improved. Follow along!!!

Customer here…. I did initial ladder test looking for pressure. I ran from 90g to 94.5g in some Lapua brass I had. The Lapua brass has been abused under 215 HH loads. 94 and 94.5 were the first two that shows any sign of flattening the primers. No catering and no ejector marks yet (with this soft a Lapua brass, that's a surprise). The step in velocity between 94g and 94.5 was about 1/2 the steep size of other 0.5gr steps. Idk of I got to the point that not all the powder was burning or if I was just hitting a wide node. More validation to come. The last shot clocked at 3477 FPS. As always, do not use this load data, this is for my custom improved chamber and custom action etc. this is strictly information based on my setup.
Awesome! Thanks for your personal info on the load data. I'm basically at the same powder charges, just not the same velocities. But my brass was definitely still forming after just the first firing. Curious to see how these fully formed pieces perform!
 
Awesome! Thanks for your personal info on the load data. I'm basically at the same powder charges, just not the same velocities. But my brass was definitely still forming after just the first firing. Curious to see how these fully formed pieces perform!
what charge and velocity are you seeing? What improved case are you running(Also an LPR?)
 
what charge and velocity are you seeing? What improved case are you running(Also an LPR?)
Currently I'm at 94gr. of H1000 with a 215M in peterson brass. I was getting 3330fps on average. But that was with just the once fired case. So it was just barely formed to the new chamber. The case walls weren't even expanded to the chamber yet. The sizing die never even touched them after the first firing. But now onto the second firing, they seem to be fully expanded and I'm now sizing the whole case when I force it into the FL die. And a totally different reamer. My gunsmiths own design.
 
Currently I'm at 94gr. of H1000 with a 215M in peterson brass. I was getting 3330fps on average. But that was with just the once fired case. So it was just barely formed to the new chamber. The case walls weren't even expanded to the chamber yet. The sizing die never even touched them after the first firing. But now onto the second firing, they seem to be fully expanded and I'm now sizing the whole case when I force it into the FL die. And a totally different reamer. My gunsmiths own design.
Thats pretty good. I have 3280 something with 215 Berger in 300 Rum with 92.5 grs N570 in 28 in. Bartlien 5 R barrel. 3400 something with 181 Hammer. Hunter with H1000. I happy with that and don't need anymore to kill anything here.
 
my last group with the 215 hammer hunters was 3122 fps, 3123 fps, 3125 fps 3121 fps, 3123 fps, 3124 fps, and 3125 fps with 86.8gr H1000. I was not chasing velocity, but accuracy. 7 shot group with an ES of 4 seemed good, but it was still over 1". my supid fire forming loads shot like 1/2", same load for 1'st firing and 2'nd firing. I was using the 212 ELD-X for fire forming, but I would like to try hunting with the monos. This is why I've moved to the 180g HH, but I'm just starting the load development.
 
I decided to take the sanding disk to my action rail and bump my rings up to .944" and mount the March FX 4.5-28 where it belongs. I liked the scope too much to give up on it. I may start a gunsmithing shop now 😅😅

33C9B4D4-EABD-4762-88D7-602B5B633434.jpeg
 
Performance always comes at a cost.

H1000 is special in that it has the lowest flame temp of all the 'slow' powders.

~3600°

IIRC, N570 is up over 4100°
Reloder 33 is 3900 and gives the same if not more speed than N570 in the 300 RUM and .338 Edge for me but is dirty and not heat stable past ~88F for me.
 

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