Greetings! I am new to this board. I'm also new to owning a Tac15i. Not new to crossbow hunting (I've hunted whitetails for 4 yrs with an Excalibur Exomax and killed 4 respectable bucks). I Just recently purchased a Tac15i from Len and after shooting 100+ shots, I could not find a comfortable position where I could consistently shoulder the crossbow and have my scope come up with clarity. (I should mention I have a longer than average arm length). So I decided to buy a MAKO aftermarket AR15 Replacement Stock- It has a cheek riser and I think it may be of help with my anchor point. Now, here is my problem: It looks like you need a specific spanner-type wrench to remove the butt of the stock. It's threaded into the receiver but it's locked in place by a ring. Does anyone know what I need for a tool to remove the stock? Any help is much appreciated!