The stock Dillon case insertion spring has two issues. One, it doesn't last nearly long enough, and two, there's not enough pressure.
We have solved both of those issues. The FFB spring uses the same spring rate as a 10 lb 1911 main recoil spring and is made from premium spring steel.
The product photo illustrates the difference in overall length and spring wire diameter.
This is a direct replacement for Dillon p/n 13567.