300 Norma Mag improved 245 berger EOL load

[Rusty85]

What speeds did you end up with using Berger 245? I've been looking at building one but a 28" tube. I'm hoping for 3050+. Considering 300 Terminator if NMi can't get there.

I'm at 2960 with my 27" 300 HCA (Norma Imp). But my other node is 3020 if I wanted to push the brass harder.

 

[DirtNap35]

I'm at 2960 with my 27" 300 HCA (Norma Imp). But my other node is 3020 if I wanted to push the brass harder.

I'm guessing that's with N570. How many grains you getting with the improved case?

 

[Rusty85]

I'm guessing that's with N570. How many grains you getting with the improved case?

Yes n570 and my load is 88.7, when I ran my pressure ladder I started to see pressure at 91 and 92 grains had a cratered primer and a good ejector mark but bolt lift was normal. Velocity at 92 was 3044. That's with Lapua brass and cci 250's. I'm really happy with my 2960 fps, it repeatedly shoots in the .3's to low .4's with an SD of 8.

 

[Longrangers]

Yes n570 and my load is 88.7, when I ran my pressure ladder I started to see pressure at 91 and 92 grains had a cratered primer and a good ejector mark but bolt lift was normal. Velocity at 92 was 3044. That's with Lapua brass and cci 250's. I'm really happy with my 2960 fps, it repeatedly shoots in the .3's to low .4's with an SD of 8.

Possibly my next build.

 

[bharris]

Greetings. Reviving this old thread, as I am building a 300 Norma as we speak, and am heavily considering the 245 projectile. When I use the Berger twist rate stability calculator on a 26" barrel and 2950 FPS, the 1:8 is as stable as the scale goes at 2.12, with the 1:9 falling down to 1.68 with 1.5 being the top of the "marginally" stable measurement. So the question is, other than the ability to use lighter projectiles in the 1:9, why have some of you chosen the 1:9 and not the 1:8 to shoot the 245's?

Just desiring to build the most appropriate set up possible for such an expensive build.

Thanks!
Brad

 

[Quicksilver338]

1:9 has stabilized mine fine out past 1000yds. Haven't taken it past transonic to see how it is out there. For hunting it will stabilize fine, ELR I don't have experience with that.

 

[DirtNap35]

Don't forget to look at elevation and temperature as it will impact twist. I went with 1:8 on mine, but I'm at 1000 ft

 

[Mike D Texas]

Greetings. Reviving this old thread, as I am building a 300 Norma as we speak, and am heavily considering the 245 projectile. When I use the Berger twist rate stability calculator on a 26" barrel and 2950 FPS, the 1:8 is as stable as the scale goes at 2.12, with the 1:9 falling down to 1.68 with 1.5 being the top of the "marginally" stable measurement. So the question is, other than the ability to use lighter projectiles in the 1:9, why have some of you chosen the 1:9 and not the 1:8 to shoot the 245's?

Just desiring to build the most appropriate set up possible for such an expensive build.

Thanks!
Brad

Mine is 1:8 because I wanted the ability to shoot big monos.

Ryan Pierce has Benchmark Carbon barrels in 1:8.5 if you wanted to split the difference.

 

[COBrad]

I'm using an 8 twist but I live at 6000 feet. Bullets are stable at a mile.