Board Thread:General Nerf discussion/@comment-44319557-20200117183101/@comment-30049823-20200117191227

If you wanna know which RIVAL blasters can fit a RIVAL red dot sight, I think all of them can.

If you ONLY wanted to know about off-brand blasters, then it's pretty slim pickings, but the Regenerator /Justice rail will sloppily hold a Nerf red dot sight, although you'll want to stuff some toilet paper or tape under it to make sure it doesn't rattle off. (And they look a little like an HK G36C)  See this thread for more details.