Bullet stabilization and 300 Norma Mag

[ZAR LRH]

I'm busy with 300 Norma project and looking at sourcing a barrel for the project. The idea would be to shoot 230gr Berger ultimately. The ideal I suppose would be to try and get hold of a 1:9 twist but that easier said than done.

I get the reduction in BC brought about by the bullet yawning as explained by Bryan Litz. Is it correct to say that reduction in BC will become less down range as the bullet starts to "sleep" and that the bullet will have the original BC once it has stabilized downrange? If so, is there a way of determining that point/distance where a bullet begins to sleep as well as grow curve of the BC? Can one then make allowance for this? Surely this will have impact down range.

With Regards to the 300 Norma brass issues, especially with regard to the primer pockets, has this been resolved? Is there other way in which this can be managed like reamer specs etc. instead of just reducing loads?

 

[gohring3006]

All of it is subjective to the environment and and your particular barrel/load combo.
The best thing you can do is, verify your actual BC thru drop and velocity data. And run the 230 thru the ballistic calculator to help you with that determination.

Ps. I switched to the 225 Hornady Bthp, which stabilizes in my 10 twist 300 Weatherby. I came up with a BC closer to .710 rather than the advertised BC.

 

[FEENIX]

The ideal I suppose would be to try and get hold of a 1:9 twist but that easier said than done.

I have Lilja SS 27"1:9" 3-groove Sendero for my .30 Lara (.300 Jarrett improved) build this year. I'm sure there other barrel manufacturer's that has 1:9" twist out there but might have to special order it and timing is everything in time for the upcoming hunting season.

 

[ZAR LRH]

Gohring3006, yes the environmental changes is my current concern. Sitting next to coast where all my load development will be conducted as well as drop charts. Hunting anywhere from here up to about 6800ft above sea level in temperatures ranging from 35*c to -10*c potentially. Yes a app will be able to adjust for the changes but not for the change in BC until the bullets starts to sleep. That is if I'm going the 1:10 route.

Thanks for the heads up on the Hornady.

FEENIX, yes the other guys also do .308 in 1:9 but if you guys are struggling that side to get hold of one it's even harder to get hold of one this side. Given this l'm trying to quantify the effect of 1:9 twist vs 1:10 twist when shooting the 230gr.

Any other LR bullets on the horizon that would warrant the additional effort and time to either wait for 1:9 instead of settling on a 1:10?

 

[gohring3006]

As far as the bullets going to "sleep".
That is a subject that tends to ruin friendships...
I would go to the custom search and type "Shoot thru target challenge"...

 

[ZAR LRH]

Thanks gohring3006! With sleeping I'm referring to the bullet not yawning anymore.

Thanks for the reading!

 

[Edd]

What contour barrel are you wanting? The first two places I looked had 8", 9", and 9.5" twist barrels in stock.

 

[FEENIX]

FEENIX, yes the other guys also do .308 in 1:9 but if you guys are struggling that side to get hold of one it's even harder to get hold of one this side.

You did not mention where you at. Not sure what struggles you are referring to but as Edd noted, other manufacturer's have them on their inventory.

What contour barrel are you wanting? The first two places I looked had 8", 9", and 9.5" twist barrels in stock.

Most has to be special ordered based on demands.

 

[ZAR LRH]

Sorry guys, sitting almost "half way" around the word in South Africa. Yes, we are blessed with game this side but components is a real problem.