Barrel length vs Stability?

[Tiny Tim]

With a patched round ball, that is the ideal twist.

Buddy of mine was into rendezvous big time. That's what he shot and it was remarkably accurate. Plenty good for Midwestern deer hunting.

 

[memtb]

I have nutt'n for ya except Welcome from North Central Wyoming.

For technical info you have landed in the correct forum…..lotsa bright folks here more than willing to share their knowledge/expertise. memtb

 

[Rabbitslayer78]

If you use my app
Eagleballistics it does this for you you can play with velocities and twist until you find what you like it even gives you rpm's

Www.eagleballistics.com
View attachment 563858

When will the android version be available?

 

[1mechanic]

Length of the barrel doesn't affect stability it's the twist, once the bullet starts twisting it's spinning at the barrel twist.

 

[mdmiller]

Welcome from Illinois!
You will find everything you need here!!

 

[ObiWanKannoli]

Try and keep RPMs to around 300k-320k max if using cup & core bullets.

(Velocity x 720) ÷ twist rate.

Thin-skinned copper jackets can start to let loose above that 320-330k RPM rate.

Monos do fine on fast twist.

Heavier bullets need faster twist to stabilize properly.

I have a bunch of 6.5mms w. 1:7.5" twists. The 130s do just fine in them.

Fastest RPM round I shoot is a 22GT w. 1:7". 77TMKs @ 3200 are at 329k RPM. They are wicked accurate still, and absolutely crush coyotes with the terminal velocity on impact.

If a 1:10" .308 won't shoot a 140gr well @ 3000fps, I highly doubt the twist rate is to blame. That is only going to be in the 216k RPM range. Pretty slow spin rate actually.

This is great information.

Twist should be fast enough to stabilize the projectile of a given weight and length, but not fast enough that it is defeating that projectiles construction. I wouldn't go into Plato's cave too much further than this on the topic, especially for 308 win.