JP Rifles has an offset mount that drops down and puts the optic 45* to the bore so you should be able to zero pretty easily, at $60 it's pricey though.
From Amazon for $9.99, this could be a reasonable solution.
Mine just arrived for mounting my Vortex SPARC as a B/U Sight at 45 degrees. Until I actually attempt the mounting, I can't say for sure whether there will be enough clearance from the existing scope for the SPARC to mount up properly. If not, I'm only out $10. With Amazon Prime, I can send it back, no questions.
Greg
PS Does not work. The riser included with the SPARC does not clear the regular scope tube.
PPS After a long period of experimentation, I discovered that although I found another way to mount the SPARC, the offset mounting made the rifle too wide to fit into any of my hard rifle cases.
I will say this, be-careful with Burris. I run piston ARs and it didnt hold up on the HK416. They replaced it no questions asked, its just not meant for that kind of abuse.