Re: Are Hard Cast Bullets Best
Say you have two identical bullets both sized to .358 dia. one is cast for straight WW alloy with a BHN hardness of say 10 and the other is cast from straight Linotype alloy with a BHN hardness of say 20+.
Both bullets are loaded in identical case,primer,powder charge. If the particular bullet is to hard for the pressure generated by the load used it want obturate enough to seal the bore properly and the harder bullet will actually shoot slower than the softer bullet that provides the correct seal to the bore although correct size is important it's not the only thing you have to consider.
There is a formula although I don't remember what it is exactly,but it's a number x BHN = pressure required to effectively cause the bullet to obturate properly. Thats why some commercial cast bullet maker offer different BHN bullets,the softer BHN bullets are designed to be shot at lower velocities and lower pressures that will generate enough pressure to cause the bullet to obturate,for higher velocities a harder bullet is needed to take the pressure created by the load,leading in not caused by friction as most people assume it caused by gas cutting or blowby. As the velocity and pressure goes up so should the bullet hardness.
Proper bullet size,hardness and lube all come into play. I shoot pure lead,in between and hard cast bullets in all my handguns semi and revolvers,leading has never been a problem as long as you match you bullet BHN,lube and load properly.