Before getting into RS, I ran a lot of airsoft guns; not run-of-the-mill airsoft guns, but reputable ones from brands such as KWA, WE, and even a VFC. I can tell you now, that those madbulls will indeed not fit on a RS Ar-15 because there is no hole drilled for a gas rod. However, since the 15-22 does not have that, you'd be able to install it just fine. Also as a word of caution, I recommend that you buy from reputable brands such as Madbull where their products are actually licensed meaning that their compatibility is much better. They build these rails for GBB (mostly AEG) M4s which with some mods to the buffer and BCG can kick equivalently to a .22. From what I know, the rails are real-spec meaning that the threads will work with RS receiver threads. As said, avoid any ACM ****, because they are not of the highest CQ, and may not be real-spec, so the threads and RIS will not run flush.