Is your collapsible stock on you Sport AR (or any other make of AR) loose or wobble? Here is a good tip on how to fix this problem;

How to fix a loose stock on your AR 15 rifle. No more wiggle, just a rock solid stock! - YouTube

I see LOTS of problems with that "fix", because LOTS of experience with Electrical Tape has shown that the adhesive WILL migrate and gum up the works. IMO a more correct solution for that rattling stock in the video is to purchase and install a buffer tube that meets the specifications for a correctly made buffer tube. BTW, I use DPMS Mil Spec buffer tubes in all of my builds and haven't had a loose butt stock on any of them.

I've had good luck using strips of painters tape applied to the inside of the stock. Lengthwise in the bore the buffer tube goes into. Has held up fine literally for years. Much different adhesive than electrical tape which I wouldn't use.

Thanks tomcatt51, I will have to try that.
scooter123, I will remember your advice as well on my next AR build.

another thread made me think about using HEAT SHRINK on the buffer tube .NO sticky mess and it grabs tight.

I used duct tape on mine, tightened it right up !

I have a CTR on my 300 BO. I has a layer or two of painters tape and needs another.
And yes, the tube and stock are the same spec.

My S&W M&P sport did not come with a Magpul stock, so I just modified what I had. No issues, and didn't cost me anything !

I agree the CTR as well as other Magpul stocks, STR, ACS. among others lock up very tightly without any additional mods. I replace all my standard sucks with a combination of those 3 stocks.