Twist rates in 224

Reloading equipment, methods, load data, powder and projectile information.

Re: Twist rates in 224

Post by deye243 » 21 Jan 2019, 6:40 pm

duncan61 wrote:He had a fancy set up and lots of people were interested in his rifle but at 800 it just sprayed them all over


And the reason it did is because 1:9is nowhere enough to stabilise a 224 80g pill you need 1:8 or more and speed should also be around 2800fps .....
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Re: Twist rates in 224

Post by SCJ429 » 21 Jan 2019, 7:06 pm

deye243 wrote:
duncan61 wrote:He had a fancy set up and lots of people were interested in his rifle but at 800 it just sprayed them all over


And the reason it did is because 1:9is nowhere enough to stabilise a 224 80g pill you need 1:8 or more and speed should also be around 2800fps .....


If it couldn't stabilise the bullet, wouldn't it spray the bullets all over at 100 and not just 800? It is very difficult to shoot anything well at 800, many a shooter of a 308 has been left wondering what went wrong at that distance in switchy winds.
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Re: Twist rates in 224

Post by deye243 » 21 Jan 2019, 7:19 pm

Depends on air temp and other things as well such as how fast the rotation is slowing which will make it worse the further out it go's .
And another thing that shooters get wrong is they think if a pill groups its stable , I had a 243 1:10 That would group the 95 Berger 95g VLD in the .3 .4 moa but at 700 had more drop than a 87g VMAX turns out that the bc was just .403 because of bullet insabilaty instead of .434
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Re: Twist rates in 224

Post by SCJ429 » 21 Jan 2019, 8:07 pm

Wouldn't the lower BC be caused by a lower velocity?

In regards to old mates 223, the bullet would be well and truely supersonic at 800. I would think that stability issues would be evident at other distances. What would be happening at the 800 metre mark to cause the groups to fall apart?
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Re: Twist rates in 224

Post by bladeracer » 21 Jan 2019, 9:42 pm

andym79 wrote:So how much RPM is too much?

Relating to how much twist is too much at 50-300 yards not 1000, how slow can you spin it or fast depending before its too slow to buck the wind or too fast and affects accuracy?

Is a 1:8 too fast, would a 1:10 be better?


Depends on the bullet, and possibly the bore finish. 52gn bullets swaged out of .22LR brass disintegrate at about 3200fps in my 8"-twist ruger, keep them under 3000fps and they're fine. Around 275,000rpm is the limit for those I think. But the 35gn Hornady's stay together just fine going significantly faster. The faster you can spin the bullet, the longer it will remain stable.
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Re: Twist rates in 224

Post by straightshooter » 22 Jan 2019, 6:21 am

I have a 223 with 20" long 1 in 9 barrel.
With not quite maximum loads;
Win mag 40 grainers disappear without reaching the target. They can probably be loaded back but I haven't bothered. They shot perfectly in the original 1 in 12 barrel but none of the following did.
ADI 62 grainers, 68 and 69 grainers from Sierra and Hornady all shoot satisfactorily. Hornady 75 grainers group very poorly.
I haven't bothered with other projectiles but you should be able to see a developing pattern.
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