300 Norma Mag Improved. Follow along!!!

So it's holding 1/2 MOA at 300 yards without tuning the seating depth yet. That's pretty solid. I would imagine the ES's would tighten up too once the brass is fully formed also.
 
So it's holding 1/2 MOA at 300 yards without tuning the seating depth yet. That's pretty solid. I would imagine the ES's would tighten up too once the brass is fully formed also.
Yeah, I can't complain for sure. I'm going do a seating depth test with both loads next go around. And I've now got two firings on all the brass I plan on using.
 
Seating depth test with 88.7 grains of n570 showed that it liked the bullet seated .03 to .035 off the lands the best. I'm getting an SD of 7 at 2960 fps with that load now so my velocity leveled out after the brass has fully formed. I'm going out tomorrow to test those two depths again.
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Went and double checked my load today at 300 yards. For some reason I was doubting my windage was good, so wanted to step back a bit and check, but not too far other factors could alter it much. I'm glad I did because it shows it was just fine haha.

245 bergers, 89gr N570, Cci 250, Lapua brass, .025" jump 2960fps
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Rusty85 what's your shoulder angle and freebore with your improved chamber. You shooting an 8 twist barrel?
 
Rusty85 what's your shoulder angle and freebore with your improved chamber. You shooting an 8 twist barrel?
35 degree shoulder but Mikes design also pushes the shoulder forward and shortens the neck. Not sure on the freebore but 245's are sitting above the neck shoulder junction. And mine's a 27" 8 twist barrel.
 
congrats!
what copper bullet were you using?.

I plan to load some 230 grain cutting edge lasers for mine. Barrel from Mike @ HCA will be here Thursday.
Just the 181 hammers. That 230 cutting edge is a HUGE bullet!!

Nicely done sir. Hoping to air out a 230 from my NMI on a WA. Buck here in a few weeks.
They work! Let me tell ya lol.
 
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