Benelli thread diameter?

[Gman]

The Williams Fire Sight dots are too small for me to focus (mid 60's eyes) on a gobblers head so they are coming off my H & K Import, M1 Super 90, Montefeltro 20 gauge. I want to replace the original screw in sight with a larger diameter red or green dot to aim. This bbl is 24" long and has a vent rib with a middle bead and the factory Benelli red "tube type" screw in front sight.

I have read that the older Benelli's use a metric thread 2.5x .45, but I don't know if this is true.

Would someone Please confirm what size thread is in this older Monte for me?

Once I determine the thread size, I need to pick out a larger diameter "Bead" to be able to aim. So I am assuming that my options may be limited if the factory thread is metric.

[Gman]

I have confirmed that the thread size is 2.5mm x .45mm.

Looking at all brands including HIVIZ, TruGlo, or any other manufacturers that you all might know?

[the Ward]

It's not a screw in bead, but i have the Champion Easy Hit 3mm fiber optic bead on several shotguns. It comes in two lengths if i remember correctly, a 5" and a 3" I think. I have the shorter ones. The are held on by super strong tape, and are not moving once installed. I'm in the same boat with the old eyes issue!

[Gman]

I have seen the sights that are held on by 2 face tape and I was a little concerned that it would eventually get knocked off by a tree limb while walking.

The other concern is that my ventilated rib is NOT smooth on top, it has the machined tiny grooves. (not sure of the proper terminology) That might make the adhesion from the tape not grip as strong?

[the Ward]

I haven't had any issues with them moving so far. One is mounted on a Benelli Vinci, it has a cross hatched type rib finish i think. And the other is on a bps10. both have stayed secure for several years of use.I often run a red dot or scope on the vinci though, it is a dual purpose waterfowl turkey gun, and i just switch up between seasons. the bps 10 i have 2 barrels for, and i use the short barrel with the easyhit bead for turkey. I don't think it would be an issue as long as barrel is clean and degreased before applying sight. I have run a truglow clamp on sight that has a screw in front bead,and the rear sight had a interchangeable peep or v that worked real good with the peep installed on my bps upland, might also be good for you.

[Gman]

I haven't had any issues with them moving so far. One is mounted on a Benelli Vinci, it has a cross hatched type rib finish i think. And the other is on a bps10. both have stayed secure for several years of use.I often run a red dot or scope on the vinci though, it is a dual purpose waterfowl turkey gun, and i just switch up between seasons. the bps 10 i have 2 barrels for, and i use the short barrel with the easyhit bead for turkey. I don't think it would be an issue as long as barrel is clean and degreased before applying sight. I have run a truglow clamp on sight that has a screw in front bead,and the rear sight had a interchangeable peep or v that worked real good with the peep installed on my bps upland, might also be good for you.

Good info, Thank You for providing all of these options! I will be reading as much as I can on the puter'.