Twist rate affecting bullet expansion

[25 Sharps]

No they weren't they same soft points, but I would imagine they would be of similar construction as 223 and 222 aren't hugely different ballisticly

It isn’t really the cartridge they are loaded in it’s what type of bullet they are and their intended purpose. You can get ‘hunting’ bullets in .224, loaded fin .223 and .222 for deer etc. that are designed for controlled expansion. You can also get ‘varmint’ type bullets loaded in the same cartridges designed for violent expansion.

Jacket thickness and impact velocity above all else like HP/SP/ polymer tip & rotational speed will determine are of expansion.

 

[25 Sharps]

No they weren't they same soft points, but I would imagine they would be of similar construction as 223 and 222 aren't hugely different ballisticly

As an example, 2 sierra 55 gr soft points.

22 CAL 55 GR VarmintKing (SVK)

The Bulletsmiths®. Reloadable bullets for rifles and pistols designed for precision target shooting, hunting, and defense. Crafting a tradition of precision since 1947.

sierrabullets.com

22 CAL 55 GR SBT GameKing (SGK)

The Bulletsmiths®. Reloadable bullets for rifles and pistols designed for precision target shooting, hunting, and defense. Crafting a tradition of precision since 1947.

sierrabullets.com

The first is designed to expand violently at .222/.223 velocities and the second at 22-250 velocities (3-500 fps faster).

Load the gameking in a .222 or .223 and it will act like a hunting bullet and punch through a fox or small deer, the varminter likely won’t exit.

 

[Donkey Basher]

I had a Ruger M77 VT in 243W that I gave away in the end. It was phenomenally accurate but it had a 1:8 twist & the carcass damage it did was horrendous as a consequence of the increased spin causing the jackets to break up after the initial impact.

 

[KimE]

got any pictures i'd be interested in having a butchers?

i'm also interested in any info anyone might have on the 190gr 308 hornady sub bullet at sub velocities

 

[KimE]

As an example, 2 sierra 55 gr soft points.

22 CAL 55 GR VarmintKing (SVK)

The Bulletsmiths®. Reloadable bullets for rifles and pistols designed for precision target shooting, hunting, and defense. Crafting a tradition of precision since 1947.

sierrabullets.com

22 CAL 55 GR SBT GameKing (SGK)

The Bulletsmiths®. Reloadable bullets for rifles and pistols designed for precision target shooting, hunting, and defense. Crafting a tradition of precision since 1947.

sierrabullets.com

The first is designed to expand violently at .222/.223 velocities and the second at 22-250 velocities (3-500 fps faster).

Load the gameking in a .222 or .223 and it will act like a hunting bullet and punch through a fox or small deer, the varminter likely won’t exit.

I shot a small (10-12kg)beaver with the 55gr gameking in 222r, hit the neck the bullet came apart one piece changed direction 90 deg. entered the brain instant death but not so tough bullet.

 

[Norfolk Deer Search]

Was watching a podcast by Barnes bullets with a guy from vortex ( Ryan Muckenhirn) discussing bullets and rotational velocity was touched upon, which I take it as the faster a bullet is spun the more likely it is to expand or blow up in some cases, I know bullet construction has a lot to play in it and like most things it's never straightforward, I found it very interesting and just from my own limited experience the other night I shot a fox with my new tikka 223 1 in 8 twist, with a remington 55 grain soft point and it expanded way more than I ever experienced before, basically almost blowing up on a chest shot and this is out of a 16 inch barrel, so probably 200 fps slower than factory velocity, my .222 with 50 grain soft points through a 1 in 14 barrel would usually get a pass through on a chest shot, interesting on others thoughts on it

I’ve been loading Barnes bullets for 15 odd years Personally I’ve never worried about it and too this day I still don’t!

 

[25 Sharps]

I shot a small (10-12kg)beaver with the 55gr gameking in 222r, hit the neck the bullet came apart one piece changed direction 90 deg. entered the brain instant death but not so tough bullet.

Sounds you hit bone ?

 

[KimE]

Sounds you hit bone ?

Yes the bullet hit the spine in the neck.

 

[25 Sharps]

Yes the bullet hit the spine in the neck.

Not that surprising that it broke up then, would be interesting to see what a lung shot would do in comparison.

 

[Bowland blades]

i would argue this has nothing really to do with rotational speed and is more a function of fragile varmint bullets at high velocity


bullets can be over spun though and never reach the target , observers claimed they saw a grey cloud just infront of the muzzle

Too fast added with a fast spin and the bullet will "dust " you can catch it through the scope and I have seen it with some match bullets . i think there is more too it but its a kind of dumb thing to do intentionally

 

[tackb]

That looks like the shape of the bullet causes the spinning once it opens , angled petals

 

[KimE]

Not that surprising that it broke up then, would be interesting to see what a lung shot would do in comparison.

Yes it just shows 222r are marginal on beaver I prefer 300blk with 110gr varmint bullets.

 

[Cold Forged]

Out of curiosity, here's a comparison of the rotational kinetic energy ("the blender effect") for blackout calibers:

300BLK (1:7 twist) → ~1% of linear energy
300BLK (1:5 twist) → ~2% of linear energy
8.6BLK (1:3 twist) → ~6% of linear energy

The latter is not entirely negligible - it would be like going from 2600 fps to 2677 fps.

PS. Rotational kinetic energy scales with the square of the bullet diameter, so calibre matters more than mass here. If a 10BLK with a 1:3 twist existed, its rotational energy would be on the order of ~9% of linear energy.

 

[Edinburgh Rifles]

I had a Ruger M77 VT in 243W that I gave away in the end. It was phenomenally accurate but it had a 1:8 twist & the carcass damage it did was horrendous as a consequence of the increased spin causing the jackets to break up after the initial impact.

Its an assumption, but without a comparison in a 1:10" .243 with same Terminal Velocity and minimising/excluding all other variables, thats all it is am afraid.

I run a 1:8" 300NM
200gr ELD-X at 3250fps
178gr ELD-X at 3435fps
No more frangible with any of the ELD-X/ELD-M than any other rifle/calibre I have using same bullet with MV of 3000+

I run a 1:7" 6.5 Grendel, nothing obviously over spun even VMax