What twist for...

14 April 2006, 01:11

fritz454

What twist for...

I'm getting started on another bunch of rifles here shortly but I think I've been using twist rates that are on the slow side after reading some of the recent post here about that subject.

What would you suggest for a 475 M'bogo I use a 14 last time but am thinking to go to a 10?

Also a 500 A2. I again used a 14" but think a (" bight be a better option.

Lastly for a 550 mag. My first one had a twist of 16" but I think I may need to get that to 12" or so.

No real reasons to change, all my other projects have shot just fine but I want to use these specifically for heavier bullets than normal for caliber. Also the bullets will be mono metal and so long for weight.

All thought are appreciated.

John

14 April 2006, 01:15

500grains

470 mbogo - 1:10
500 A2 - 1:10
550 mag - 1:12

My purpose: Keep long bullets, such as brass solids, stable in flesh, especially when hitting bone. Side benefit: decreased bullet yaw in the event that you use very high velocity loads. Downside: slightly higher pressure, but not an issue unless your loads are right at the very edge of the safety limit.

15 April 2006, 00:18

woodsracer

I was discussing this same topic with Mr. Mbogo himself about the .470 Mbogo and he noted this in a PM:

quote:
HI Jeff,
I don't think the 1 in 10 is too much. With all the modern bullets and the low pressures the Mbogo works with a 1 in 10 would be a good choice. the bullets will stand up and the pressures will still be moderate. I would consider it for sure.

He also noted that a #6 contour should be about right for the barrel. You want a diameter of at least .750 at 24 inches.

15 April 2006, 04:07

fritz454

Thanks guys,

I haven't had any noticable problem with the slower twists but since I want to run heave for caliber bullets anyway I figure a faster spin will help.

I'm going with 475-10" / 510 -10" / 550 - 12"

Thanks

15 April 2006, 04:10

woodsracer

quote:
Originally posted by fritz454:

I haven't had any noticable problem with the slower twists but since I want to run heave for caliber bullets anyway I figure a faster spin will help.

I'm going with 475-10" / 510 -10" / 550 - 12"

Sounds good to me!

15 April 2006, 07:26

.366torque

quote:
Originally posted by fritz454:
I'm getting started on another bunch of rifles here shortly but I think I've been using twist rates that are on the slow side after reading some of the recent post here about that subject.

What would you suggest for a 475 M'bogo I use a 14 last time but am thinking to go to a 10?

Also a 500 A2. I again used a 14" but think a (" bight be a better option.

Lastly for a 550 mag. My first one had a twist of 16" but I think I may need to get that to 12" or so.

No real reasons to change, all my other projects have shot just fine but I want to use these specifically for heavier bullets than normal for caliber. Also the bullets will be mono metal and so long for weight.

All thought are appreciated.

John

Holy S**T!!! A 338 Win must feel like a 243 for you!