Never tried it, but as a sighting device technically a laser would work exactly at one distance, though with a large enough kill zone you would probably get a short distance range where the laser would work as an aiming point.
As for mounts you could try UTG clamp on barrel mounts that have pic rails. Quite cheap on Amazon and they will accommodate a range of barrel diameters. You might want to use some sort of tape inside to avoid marring the barrel finish. Since the mounts are designed for firearms, I imagine they won't move under the harsh recoil of a Diana 48/52/54 ( I am guessing that from your mention of a sidelever).
Worth a try. Laser and mount together will be quite cheap.
Does anyone do this? I have an occasional need to eliminate a pest in low light, it seems like this might be the way to go, while still allowing any type of sight on the rail. What mount would work?
thanks
I hesitated to post a comment because I thought I must be missing the point, but does the laser have to be mounted underneath the barrel--separately that is--to accomplish what you're after? Although I've never done it, and neither can I point you to the right parts, in my mind's eye I have images of at least one nicely-elegant AND functional way to mount a laser in combination with a scope on the same rail utilizing some of the same hardware in a 'piggy-back' fashion. In fact, I believe I've seen it portrayed as being done that way in (excuse me) TV shows and movies by SWAT personnel and the military numerous times, usually with a similar appearance in the way of mounting hardware.
The one caveat that comes to mind is that you don't mention the model/recoil level of the air gun in question, and I think it needs accommodated by the laser you choose, since I seem to remember that some laser sights don't hold up well to recoil, 1-way or otherwise (the latter case being a reference to the 2-way recoil of springers).
I like the idea of mounting a laser on a scope. I haven't put a scope on this one yet, it's a B21 (RWS 48 clone), and might not. But now that I've started to think it's a good idea I probably will try on one of the others.
I don't have a laser yet, still just thinking. But none of my scopes have illuminated crosshairs, and a couple of times I've been able to see a critter but have no idea where the point of aim is, so I was thinking a laser would add a bit more aimability in dim but not full dark light.
No, it doesn't have to be underneath, but underneath it doesn't interfere with other sighting systems. Of course that won't work for a pumper! Too bad. Droop might be a problem underneath also.