I have killed quite a few deer with Spitfires, both regular and the Max. Never had a problem with them.
I use the spitfire 125s and they are deadly. They open huge holes and never had a problem with them not opening. Well worth the money.
Switched over to the spitfire maxxs cut on contact tip last year from the rages...and man I am glad I did! shot 3 deer with them and had complete pass through's with great blood trails. The only thing i wish about them is that they make a bigger entrance hole but the exit hole is extremely devastating!