First Custom Rifle Build | Tips Appreciated

[LongBomber]

There is no downside to be 1:8 instead of 1:8.5. But 1:8 will allow you more versatility in bullets, especially if you live/shoot near sea-level.

There is some good info in the applied balistics books, I can have a look at those bullets in their book and see what the optimal twist rate is. There is stable and not tumbling and then there is the stability that will give you the full bullets BC.

But honestly the 8 twist is the way to go in a 6.5cm. If you were going to a large 6.5 (26N or 6.5-300) I would rather be 1:9 or 1:10. But I live at 3000' and never go lower, and my 1:8 26N is very hard on the 140 bergers it will dust the odd one mid-air.

I "think" I've settled on the build. Though there are two things I'm still not sold on yet, as I've decided to make this a 300 yard max hunting rifle (most shots will be under 150 years) and just do another PRS build for a 1,000 yard toy.

Action: Defiance Anti
Barrel: Carbon Six 18" Carbon Barrel, 1:8" twist, threaded for 5/8"x24 (Contemplating 16.5", plus my 7.5" suppressor would put me at an OAL of 24")
Stock: AG Composites, AG Adjustable Chalk Branch Carbon Fiber Stock
Trigger: Trigger Tech Diamond
Bottom Metal: Hawkins
Magazine: MDT
Suppressor: Energetic Armament VOX-S, with Dead Air KeyMount Muzzle Brake

Two things about barrel length I'm still hung up on:
1. The Carbon Six twist rate calculator says I should do 1:8.5 for the barrel and bullets I will be using. I'm don't understand why folks keep saying 1:8 or 1:7.5. I'm sure you all have good reasons for the 1:8, I just understand why the twist rate calculator shows something different. Help me understand please!
2. Contemplating a 16.5" barrel. Once I add my 7.5" suppressor, I would be at an OAL of 24". This would be great for my normal hunting conditions.

 

[ModernRedneck]

There is no downside to be 1:8 instead of 1:8.5. But 1:8 will allow you more versatility in bullets, especially if you live/shoot near sea-level.

There is some good info in the applied balistics books, I can have a look at those bullets in their book and see what the optimal twist rate is. There is stable and not tumbling and then there is the stability that will give you the full bullets BC.

But honestly the 8 twist is the way to go in a 6.5cm. If you were going to a large 6.5 (26N or 6.5-300) I would rather be 1:9 or 1:10. But I live at 3000' and never go lower, and my 1:8 26N is very hard on the 140 bergers it will dust the odd one mid-air.

That makes sense! I'm 7' above sea level. Thanks