@Kratonage, Travis is right on. Most of your butt connectors are only rated on average around 15-20 amps. For comparison, your 3.5mm bullet connectors offer 60 amps continuous.
I find bullet connectors and EC type connectors very easy to install. If you're having troubles I'd recommend taking a look at the thread "How to Solder Correctly" over at RCNitroTalk.