if i use the LEE FACTORY CRIMP for to crimp my cartridges, after the crimp the initial velocity increase or decrease?

You will most probabely have higher velocities. But that's not the issue. What you will definenely get is higher pressure. That's were the highr velocity will come from. BUT, velocity is not a function of pressure. Threfore you may have a presure incraese of 15 or 20% but only a minor increase in velocity of 3%.

for me is important that after the crimp the velocity do not decrease.

quote:

What you will definenely get is higher pressure. That's were the highr velocity will come from. BUT, velocity is not a function of pressure.

Not really. First of all, having shot several different cartridges uncrimped or crimped with the Lee Factory Crimp die, I have never noticed any signs at all of any pressure difference. Secondly, velocity IS a function of pressure.

The velocity will not decrease in a crimped cartridge.