I opened my Benelli M2 Field, and realized it isn’t drilled and tapped to take a rail for the red dot. I want to mount a Fastfire. Any ideas?

Thank you, hive!!

Burris has their speed bead system that mounts between the stock and receiver. Specifically you need their 410672 version for the M2. For the money you could always just have the receiver drilled and tapped for a more modern mount.

https://www.burrisoptics.com/mounting-systems/speedbead-mounts?sub=40

Holy cow Burris wants 108 bucks for that.  
Yeah, brownells has blank pic rail.  If you have a drill press and modest skills it would be easy to add a rail. I would tap 4 holes for the pic rail.

Acro S2 mounts to the shotgun rib.

https://aimpoint.us/acro-s-2-9-moa-red-dot-reflex-sight-with-integrated-shotgun-rib-mount/

ETA: understood the orig question, providing alternatives.

I drilled & threaded a Remington 870 and it wasn't a big deal to do. I called around and people wanted too much money to do it for me. Just get the appropriate Picatinny rail, the proper thread tap for the screws and use the right size drill bit.

1. I measured and scribed a pencil line to mark the center of the receiver.

2. I centered the Picatinny rail over the scribed line and marked one screw location using a center punch.

3. I drilled & threaded that hole, installed the Picatinny with the scew. I lined it up and punched another screw location.

4. I removed the Picatinny rail, drilled & threaded that hole and repeated the process until all locations were drilled & threaded.

It's nice if you can use a drill press, even a cheap one along with a vise. It can be done with just a hand held drill, but a drill press & vise ensures the holes are drilled as plumb as can be. Take your time drilling and use lube. Same with threading, use lube and go slow. Once I got the thread tap started, I would thread the hole a little ways, reverse the thread tap up and screw it back in again. It went perfectly.

Yeah for the money he’d be better off just either drilling and tapping it himself or taking and having it done. Any gunsmith worth their salt should be able to drill and tap a receiver it seems scary but it’s really easy and even if you somehow messed it up, it can still be fixed though that is when you start having to bust out the money.