A quote from Jeremiah Cottle....
"We only tested the right handed version, and only on a .223/556 AR. It does work on pistol calibers, but it does not work with .22LR conversions or uppers. There just isn’t enough recoil in the .22LR to make the gun work properly."

Who is Jeremiah Cottle you ask?
The inventor of the Slide Fire and a US Air Force veteran of three conflicts

I think it is important to include some facts about what the true cost of getting this product to 'work' on the MP1522. Comments such as,,, its great! Buy one if you want to have fun! This may cause some of our younger members to jump into a project that is financially over their head.
Correct me if Im wrong here.. Im thinking that for this product to 'work' correctly someone would need to spend in the neighborhood of one thousand dollars ($1000.00), including the price of the rifle.
I do NOT own SFStock, so my information is based on what little I have read here. Owner's please feel free to add any exact cost information.

This is a very good read.
The Slide Fire Solutions SSAR-15 Bump Fire Device