Rate of Twist formula

[Alaska]

Formula for bullet to rate of twist
Nosler 200gr AB. 308
Bullet Dia DIV into the length
Then Div cabilers Long into 150
Then Multiply this by bullet Dia

It will look something like this
.308 Div into 1.490" = 4.83 Cal Long
4.83 Div into 150 = 31.05 Ideal twist rate (One turn in 31.05)
31.05 x .308 = 9.56 = 1:9 Twist Rate as the ideal twist rate for the 200gr Nosler AB

 

[ScreaminEagle]

Tanks that's some good info. Could you treat this like a math problem and given a known twist and bullet diameter, let's say 1-14 twist with a .224 diameter, could you figure out the ideal bullet weight and length?

 

[Alaska]

Yes But that bullet 1:14 the 52/53/50 grains


Need Bullet length for formula?

 

[JD338]

Jeff,

Good info, thanks for posting.
I wish Remington would rethink their twist for the 22-250 and heavier 60 gr bullets. 1:10 would be good.

JD338

 

[Alaska]

Indeed had a 22 250 in win 70 shot the 52gr Sierra HPBT on dime with H380 but as I went up in bullet weight groups open up due to that twist.........1:7 to 1:9 is my favorite with hevier 69/75

 

[SJB358]

Seems like the big companies like Winchester and Remington are missing the ball not putting a 1-10 or better on their 22-250's and such. Everyone has the 60gr and heavier bullets for really taking advantage of the case size, but not too many companies are offering the twist needed to utilize them. I ended up with a TC as they use a 1-12. Not sure how it will handle the 60gr PT, but it worked well in my Savage, so I hope it works in the TC. Scotty

 

[Alaska]

I guess alot of states 224 cal is not allowed for deer hunting maybe thats the reason.......grew up with a 22 hornet and a 222 Rem that dumped alot of deer back in NC.