Gunsmithing problem with new firing pin

[CST]

Hi...I just replaced my firing pin assembly with a new drop in unit from Midway...when the "hammer " falls on my dummy round..i noticed the bolt lift being very heavy compared to my old one.... anyone know why? perhaps the firing pin spring is so new or is there something else going on?
thanks!

 

[Sonic Crack]

The spring could be a little longer or thicker, giving you more spring pressure. The new cocking piece could also effect the "feel" also as its not wore in like the original