At age 67 I no longer could see the front sight on my Browning 65 218 Bee. It had already been taped for a lyman receiver sight. I bought a Fastfire with the idea of putting it on the Browning. I pulled the Lyman and had a Williams 5D receiver sight that I figured I could make work somehow. Pulled the piece that holds the screw in aperture disc and found 4 taped holes underneath. These holes are the same size as what Burris uses and two of them matched the spacing and centered the Fastfire over the receiver. Took ten minutes to install. This was the same Williams 5D sight that the '94 Winchester uses. This worked out very well, Once in a great while I get lucky.
Doc

"No free man shall ever be debarred the use of arms. The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government." Thomas Jefferson, 1776