Which 300 Norma Mag Twist????

[Longtine88]

I fixing to put together a rifle in 300 Norma Mag shooting the 230 Berger Hybrid OTM's in it. I live at 500' elevation in Texas but it will only be used in 6000' of elevation or higher. My 300 Win mags all use the 215's with 1:10's. They do just fine. I want this one to shoot the 230's. Stay with 1:10 got with 1:9.4 or 1:9??? I leaning one way just wanted to here from some Norma shooters.

 

[Shane Lindsey]

1:8. Lets you have heavier options.

Overspin the 245s if you ever want to and heavier if they come out.

I have a 8 in my RUM with the 245s. Very confident with it. 215s are equally good.

 

[MagnumManiac]

A 9" twist is ample. I run 230's in 10" twists without a single problem.
If you want to run 250g+ bullets, then a 8" twist is more of a good thing.
My only really fast twisted rifle is my 22-250AI, it runs a 7" twist 32" barrel. I use 77g or 80g pills in it for short/mid coarse (300-600) F-class matches.
An 8" twist is ample too, but went 7" just in case even heavier bullets come out.

Cheers.

 

[Longtine88]

A 9" twist is ample. I run 230's in 10" twists without a single problem.
If you want to run 250g+ bullets, then a 8" twist is more of a good thing.
My only really fast twisted rifle is my 22-250AI, it runs a 7" twist 32" barrel. I use 77g or 80g pills in it for short/mid coarse (300-600) F-class matches.
An 8" twist is ample too, but went 7" just in case even heavier bullets come out.

Cheers.

What elevation are you running the 10" twist with 230's?

 

[MagnumManiac]

Anything from sea level to 3000'.
My 1000yrd range is at 2800'. Have zero issues running 230's at that range, my home range is 600yrds and at sea level, have zero issues there too.

Cheers.

 

[Shane Lindsey]

I have received barrels that were ordered as a 10 twist, but when they showed up, they were 10.25.

I lean towards overspinning, especially if for hunting. I had a 10 twist 270 that on one day would drive nails with the 165 Matrix, the next day out, would hit sideways. Sea level in relatively uniform weather of San Diego County. Only think I could come up with was cooler air and humidity.

 

[Longtine88]

I think I'm going with the 9.4" twist. Trying to milk more fps out of it. If I go faster then I could lose a little.

 

[Shane Lindsey]

I think I'm going with the 9.4" twist. Trying to milk more fps out of it. If I go faster then I could lose a little.

Not enough an animal is going to notice.

 

[MagnumManiac]

Twist makes no difference to velocity.
Many tests have been run using the exact same loads in a 7" twisted 5.56 and a 10" twist and a 14" twist. No discernible difference could be seen, all the velocities varied by normal amounts and were within 10-20fps of each other.

Cheers.

 

[Vol1975]

9 will be fine

 

[Huntnful]

I'm having one built right now for the same bullets. I went with a 9 twist. Overspinning doesn't hurt, but underspinning does.

 

[DUSTY NOGGIN]

9

id send em the longest dummy you can make and have em cut throat to match

 

[L.Sherm]

I'm having one built right now for the same bullets. I went with a 9 twist. Overspinning doesn't hurt, but underspinning does.

Sure about overspinning doesn't hurt, when you hurt jacket integrity it certainly does. Ive asked many times guys who complain about Bergers blowing up what twist there running and not one person has said.
If I'm a betting man thats there problem

 

[Huntnful]

Sure about overspinning doesn't hurt, when you hurt jacket integrity it certainly does. Ive asked many times guys who complain about Bergers blowing up what twist there running and not one person has said.
If I'm a betting man thats there problem

Very valid point!! I was strictly thinking about this instance with the 230's in a 9 twist instead of 10 twist. But I made a blanket statement lol.


Bergers blowing up on animals or in flight?