Rules different for copper vs lead bullets?

[Banshee]

From reading here and quite a few other sites, it appears to me that the concept of sectional density may apply differently when comparing copper bullets such as Barnes and the new E-tip to a traditional copper jacketed bullet.

The sectional density idea in traditional bullets focuses on deeper penetration, ie, a 180 gr 30 cal bullet penetrates deeper than a 150 gr 30 cal bullet. While this is likely true for the copper bullets too, it appears to be much less of a concern since story after story of complete penetration are the norm for the copper bullets.

The Barnes website suggests that the hunter can realistically consider the lighter bullet weights because of the greater penetration.

Thoughts???

 

[Britz]

I see no reason to go to the lighter bullets other than recoil. if you want more power, more range, and less windage difference yo should always go heavier.

 

[Antelope_Sniper]

Modern bullet design significantly changes the rules. There's no question about it. In the old days, if you wanted a tougher bullet, you had to make more of it. Alot of buffalo were killed with big, slow lead bullets. Today werhave bullets that are Lead alloy, copper Alloy, work hardened copper, Partition, Failsafe, hollowpoint copper, oh yea, and those funny plastic tips. Sectional density is a measure of the bullets weight, vs it diameter. That's all it is. Nothing more, nothing less. In a world where all bullets are make of a uniform material, it might be of value, but in today world of different bullet materials and construction, it's virtually worthless.
I remember an earlier thread where where there we some pictures of various bullets fired into medium. The barnes bullets shed their pettles early, and consequently penetrated deeper then the bonded lead bullets.
In many ways this same concept applies to the AccuBond. Quick expansion to 2x bullet diameter, shed the pettles, and the remaining 70% will provide deep penetration. For these reasons I would tend to agree with Barnes. Today, you can get the job done better with a lighter bullet then your father or grandfather could.

 

[wingnut]

Modern bullet design significantly changes the rules. There's no question about it. In the old days, if you wanted a tougher bullet, you had to make more of it. Alot of buffalo were killed with big, slow lead bullets. Today werhave bullets that are Lead alloy, copper Alloy, work hardened copper, Partition, Failsafe, hollowpoint copper, oh yea, and those funny plastic tips. Sectional density is a measure of the bullets weight, vs it diameter. That's all it is. Nothing more, nothing less. In a world where all bullets are make of a uniform material, it might be of value, but in today world of different bullet materials and construction, it's virtually worthless.
I remember an earlier thread where where there we some pictures of various bullets fired into medium. The barnes bullets shed their pettles early, and consequently penetrated deeper then the bonded lead bullets.
In many ways this same concept applies to the AccuBond. Quick expansion to 2x bullet diameter, shed the pettles, and the remaining 70% will provide deep penetration. For these reasons I would tend to agree with Barnes. Today, you can get the job done better with a lighter bullet then your father or grandfather could.

+1

Only to add:

SD only applies when comparing bullets of like construction; lead to lead, copper to copper, Partition to Partition, etc.

ETA: Once you reach full penetration as in a high speed Barnes, Failsafe or E-tip pass through, your only concern should be a not too short blood trail. :lol:

 

[FOTIS]

Yes. This is why Elmer Keith used .338- 275 gr to 300 gr bullets on elk. Regular weight bullets would break up. These days I would go after elk with a 120 gr TSX/E-tip/GS custom from a 7mm-08 with no quelms. :wink: