This might be what you are looking for.
Atom Optics 1 inch Scope Rings Mounts fit 11mm Dovetail Rails for Picatinny Rail Scope Rings High Profile One Piece https://a.co/d/hJV7LM5
A customer brought this in to the gun shop I used to work at. 300BO doesn't work in a 5.56. Mark those mags and pay attention. That was a Troy Industries upper.
The pellets didnt like the no11 caps on my inline that well. I put a musket cap nipple on it. That's all I had to change was the nipple. A bit more fire to light the pellets that way.