The easiest way to put a tactical knob on a bolt is to send it to GA Precision in KC, MO. One word of caution when installing a large knob on a factory bolt is that they are too close to the trigger for someone with larger hands. I understand GA Precision will now install a complete bolt handle that is straight and not slanted back which is probably a better way to go. No idea what it cost, but it may be listed on their website.