11-02-2023, 10:39 PM
I will add that you don't want to overstabilize bullets by having too fast a twist - they resist pointing down to the target after apogee. This is more noticeable in long range shooting.
Here is Shilen Rifles advice on twist rate:
[INDENT]6.5mm/.264
- 7" * for bullets heavier than 130 gr.
- 8" for bullets heavier than 130 gr.
- 8" * Ratchet rifled 4 groove
- 9" for bullets up to 130 gr.[/INDENT]
Kreiger twist rates for 6.5 are 1:7, 1:7.5, 1:8, 1:8.5, 1:9.
1:8 is the standard as it sits in the middle of what works. Still, lighter 6.5 bullets are more suited to 1:8 and slower.
I had a 1:7.5 to shoot 140gn Noslers in 6.5x47. Turned out it was less accurate than the Kriegers. I suspect that was down to the quality of the Pac-Nor barrel and not the twist rate, but I'll never know for sure.
Here is Shilen Rifles advice on twist rate:
[INDENT]6.5mm/.264
- 7" * for bullets heavier than 130 gr.
- 8" for bullets heavier than 130 gr.
- 8" * Ratchet rifled 4 groove
- 9" for bullets up to 130 gr.[/INDENT]
Kreiger twist rates for 6.5 are 1:7, 1:7.5, 1:8, 1:8.5, 1:9.
1:8 is the standard as it sits in the middle of what works. Still, lighter 6.5 bullets are more suited to 1:8 and slower.
I had a 1:7.5 to shoot 140gn Noslers in 6.5x47. Turned out it was less accurate than the Kriegers. I suspect that was down to the quality of the Pac-Nor barrel and not the twist rate, but I'll never know for sure.