I mounted a 3x9x40 on my Encore using the Leapold QR base with QR high rings.....Have room to cock the hammer but I went ahead and put on a hammer extender anyway. I bought it from Cabelas. Much easier to cock the hammer with it on.

I haven't heard anything about T/C discouraging the use of a hammer extension. Really see noadverse affect on the rifle firing mechanisms.