Question on bullet weights & powder charge

[rvdoc]

Wondering why if for instance you use a 55 grain bullet by different manufactures and or by different designs (sp, hp, etc) that the powder min and max charge would be different? I can understand were the col would be different. Just curious. Thanks

[Shoney]

Here are most of the factors that will have influence on a bullet’s velocity:
Primer: strength, brisance - is a measure of the rapidity with which an explosive develops its maximum pressure
Barrel: length; tightness of bore; height of the lands; distance of bullet to lands; temperature of barrel;
Lock Strength: the force which is applied to the primer by various strength firing mechanisms;
Bullet: bearing surface of bullet, alloy of bullet; shape of bullet; distance off rifling;
Brass: new/used elasticity; manufacturer, volume; crimp;
Powder: new, aged, old, batch powder was from;
Weather: ambient air temp., barometric pressure, humidity
Elevation: above sea level
Other: I am sure I have not listed all

If you conduct the tests using the
1. same weapon;
2. the same brass that is volumetrically identical and fired same number of times;
3. the same charge weight of powder, from the same lot;
4. the same primer;

and you use only different brand bullets, all of the
a. same weight;
b. same distance off the lands (not same col); and
c. the barrel temperature is the same.

Here are the bullet factors that will influence velocity:
I. shape of bullet; (SP HP and et cetera {ect.})
II. shape of the bullets base (flat, BT, Concave and et cetera {ect.})
III. bearing surface of bullet,
IV. alloy of bullet;

I'm sure there are also other factors that I have not outlined.