I just received the AR15 disconnect spring, and it looks like it will fit if I remove the wider bottom last coil. However, the AR spring feels more than 25% weaker than the Wolff extra power spring, so this was a failed experiment, oh well. I still think the Speer ammo batch I got just doesn't want to run correctly in this C100. I changed my concealed carry renewal class to early December, so the C100 will not be fired again until then.