Flat/Solid VS Hollow Base boolits

[beng]

I use a 405 .459 cast in my Buffalo Classis (45-70). Was reading an article about the "hollow base 405", he was stating how it is the only cast boolit he will use, and at 100 yds. and 1300 fps it's a 1" group, but did not know how it will do over that range. I shoot a aflat / solid boolit that I use for silhouette shooting 100 yds to 300 yds. at 1350-1400 fps. What I would like to know is, "What is the difference in accuracy and why would use a hollow base boolits?" Thanks for your time.

[felix]

Pressure follows the center path down the barrel. Hollow base allows expansion of the boolit base making a firm grip of boolit to groove. Solid base allows contraction of the base instead. For low pressure curves, hollow base is better, especially when boolit is small in the base due to sizing by WHATEVER means, including case compression. High pressure curves, especially for hard boolits, need solid base boolits to track without trashing the boolit at the tail end. ... felix

[Leftoverdj]

I'll leave the theory to Felix. All I know or need to know is that Lee's 459-405-HB costs about $20, is easy to cast, and shoots better than anything else I have been able to try.