you need to include the disclaimer that you cannot pull the charging handle on an AR15 with this cheek riser installed and the stock fully collapsed!!!
I know because I have the ctr stock with this riser on my ar15 and I have it locked on the 3rd hole so I can operate the charging handle. It's killing me because I like the stock and cheek riser, but I know it's so stupid to keep it on there. If i need to use the rifle is a SHTF situation and i need the stock collapsed I'm screwed or I need to pull off the cheek riser. My name is _____ and I'm an idiot!
On a different note. If you put this on your ctr stock installed the xcr you're golden and will have a very nice cheek weld. It is very comfortable to shoot with.