Mossberg old school receiver sight screws

[Light Infantry]

Does anyone know the mounting screw sizes? For sights such as s130, s330 etc. Would they all be the same over the course of the various sights?

Thanks in advance

 

[Lever30]

Hi - I've owned several older Moss 22's, including a 42M, 46B, 146B, 151K and 151MB. The receiver sights from all of these rifles used #10-32 screws. I have a 340B as well with the S330 sight and I believe they are also #10-32. Hope that helps.

 

[trevj]

Hi - I've owned several older Moss 22's, including a 42M, 46B, 146B, 151K and 151MB. The receiver sights from all of these rifles used #10-32 screws. I have a 340B as well with the S330 sight and I believe they are also #10-32. Hope that helps.

Man, if that is correct, you are so lucky! 10-32 screws are almost as common as dirt, and you can get them almost anywhere!

10-32 helicoils, same!

 

[mcaswell]

Thanks Lever30. I have a 151M in the back of my safe that comes out once in a while. The scope on it is about as old as the rifle itself.

 

[headhunter2]

Other older Mossberg sight screw sizes are
Front sight dove tails are 0.375" wide, screw mount front sights use a 8-40 UNEF screw size.
Rear sight dove tails are 0.375" wide, rear barrel sights used a 8-40 UNEF screw size.
Receiver sights were on 0.625" centers and used 10-32 screw size.
Hope this helps others.

 

[trevj]

8-40 isn't super uncommon, though I would expect to have to pay dearly for a helicoil!

It was pretty late in the game, when gunmakers stuck to a 'standard' for their screw threads, even if it was the Extra Fine series.

At least it wasn't a UNS thread, or any 'other' thread form that allowed for "Special" thread pitches!

Which is to say, at least with a Unified National Special thread, you could figure out what you needed, based on the diameter and thread pitch.