Barrel length and twist question

[Randy Tidwell]

Feenix, I agree with you, any change will affect performance.

I just content the biggest factor is bullet lenght, not weight.

JMHO

 

[FEENIX]

Feenix, I agree with you, any change will affect performance.

I just content the biggest factor is bullet lenght, not weight.

JMHO

Sorry but you're still missing the point (but you're getting there ), it is all 4. Going back to your .308 cal round nose, spitzer, VLD analogy, even if the bullet manufacturers managed to keep them all the same weight and length, because they have different designs, they'll have different BCs.

 

[Randy Tidwell]

No, I get it completely. All aspects of the bullet design have a bearing on its inflight stability. I just contend the length of the projectile has more to do with its stability than weight or shape.

JMHO

 

[FEENIX]

No, I get it completely. All aspects of the bullet design have a bearing on its inflight stability. I just contend the length of the projectile has more to do with its stability than weight or shape.

JMHO

Twist rate is not related to bullet weight, it is relative to the length of the bullet.

You at least progressively got better from your original post in #25.

 

[Gerard Schultz]

We may offer some advice

That is why we ask questions on forums and read what others have to say. It might seem like the OP is being hi-jacked, but it is usually just an extension of the discussion/education.

A faster twist like a 1 in 8" will stabilize the high for caliber bullets but might not stabilize the lighter ones.

If a bullet is stable, the barrel will stabilize any bullet that is shorter (lighter), providing it is similarly shaped. Saying that it may not stabilize lighter bullets goes to another factor called tractability and generally becomes important with a 30 cal and shorter bullets at 500 plus.

A 1 in 10" is the middle ground and just in case he decides to go with something heavier like a 180gr bullet he will be able to, and also be able to use the 150gr with good results.

A 1:10" twist will allow the average 150gr jacketed bullet to be used up to about 600 yards. At longer distances than that, best is to switch to a heavier bullet. A 1 in 9" will allow a 150gr to be used at the same distance of about 600 yards or less, it will not hurt anything, but even longer bullets than 180gr (higher BC) can be used and will have the correct terminal ballistics.

Actually one should measure twist in calibers. For instance a 1:10" twist .30 cal (twist = 32.5 cal.) is tighter than a 1:9" twist .243 cal (twist = 37 cal.)

 

[LVJ76]

That is why we ask questions on forums and read what others have to say. It might seem like the OP is being hi-jacked, but it is usually just an extension of the discussion/education.

If a bullet is stable, the barrel will stabilize any bullet that is shorter (lighter), providing it is similarly shaped. Saying that it may not stabilize lighter bullets goes to another factor called tractability and generally becomes important with a 30 cal and shorter bullets at 500 plus.

A 1:10" twist will allow the average 150gr jacketed bullet to be used up to about 600 yards. At longer distances than that, best is to switch to a heavier bullet. A 1 in 9" will allow a 150gr to be used at the same distance of about 600 yards or less, it will not hurt anything, but even longer bullets than 180gr (higher BC) can be used and will have the correct terminal ballistics.

Actually one should measure BC in calibers. For instance a 1:10" twist .30 cal (twist = 32.5 cal.) is tighter than a 1:9" twist .243 cal (twist = 37 cal.)

Definitely better explained than me, Lol. Well put.

 

[Gerard Schultz]

The last sentence of my post above was edited after I reread it this morning. I cannot believe I made such a fundamental mistake, the lateness of the hour must have gotten to me