The T7 primers aren't as hot. Actually, ALL the "muzzleloader" 209 primers are cooler than the standard 209 shotshell primers. CCI's work beautifully in my TC and my daughters TC Impact with BH209. I've yet to have a misfire. They are the perfect length for just the right "crush" that I have set up in it. Fed 209A are supposed to be really good with BH as well.