I use the spitfire by NAP they are shooting exactly the same as my field points. Never have any issues with them not opening or poor penatration. They scared me a little the first time I shot a deer, when I found the arrow it looked like the baldes didn't deploy but after looking more closely they opened and then closed when they exited the deer. I like them but may change to RAGE slip cams next year.
Not sure what you mean when you say "replacable" I have repalced my blades on the spitfires after every deer I have shot.
Cdn1
