What are your guys thought on barrel twist rates and bullets? I guess the right question would be this. Do you think bullet weight or length has the greatest relationship to proper twist rates in barrels? What about the conventional jacket/core bullet to the newer Barnes solid copper bullets? I suppose my reason for asking is this. If the length is the most important consideration to matching a bullet to twist rate, then some of the "accuracy" problems with barnes bullets could be the length/twist/weight raito could it not? Are you confused yet? Simply put, If I am shooting a 150 grain conventinal bullet and want to switch to a solid copper bullet what factor should I look at first, bullet weight or length?

The twist is the governing factor on the weight of the bullet that will shoot the most accurate. Distance your are shooting will lend more to the length of the barrel. Under 300 yards a flat base bullet will be more accurate than a boat tail. With a 20" barrel or more the rifle will start the recoil before the bullet leaves the barrel so in come cases a long barrel it may not give you the best accuracy. Good Luck

Simply put, it is bullet length that is the critical factor. The longer the bullet, the faster the twist. This is why a barrel that will not handle a given bullet weight as a spitzer will handle the same weight in a round nose design. While the difference in construction may have some effect on stability, the difference is not that important though except as it affects the length.
In general it can be said that a projectile of a given length will have to spin at a rate that will give a certain surface speed of rotation in order to be stable. This means that a bullet 1 inch long that is .458" in diameter can actually spin at a lower rpm rate than one that is .243" for instance. Regards, Bill.

Arkie55,
Bill is correct, it is the length that is important. A lead cored 150 grain bullet is shorter than a 150 grain Barnes X.
The following website is from a South African company that makes solid copper bullets. In the table they list what they recommended for twist rate and "minimum" velocity for each bullet made. Take a look and you will get an idea of what weight/length will work with the twist rate you have, ie.- .30-06 is normally a 1-10" twist.
http://gunlinks.zibycom.com/members/002245268/Site2/hvtech.html
The velocity guidelines listed on the site is for minimum starting velocity.

[ 11-15-2002, 17:31: Message edited by: DaveC ]

That chart is a shocker at first. I looked at the 130 gr .284" bullet and it requires a 1-9 twist at 2400 fps MV. But I think the average cartridge will give a lot more velocity than that.

My 7M WSM should be able to do 3200 fps so maybe thats 3200/2400 x 1 in 9 = 1 in 12? If so we need more information as many are shooting heavier bullets than what the chart shows.

That being the case, I wonder how ballard rifling as opposed to micro groves compares in reguards to handeling longer and heavier spitzers. Would a Ballard rifled barrel have an edge in this aspect?

No. The determining factor is the twist rate not the configuration. There is no slippage to speak of. The ballard type rifling is reputed to work better with cast bullets and it makes sense that it might since cast bullets may have a tendency to strip in the micr groove barrels if the fit is less than optimum. regards, Bill.