I have a 20 gauge Remington 870 clone, the H&R Pardner Pump. From what I understand, all 870 parts are supposed to be compatible with it. But being 20 gauge, certain things won't work unless they're made specifically for the 20 gauge version.

I was thinking I should probably attach some kind of light to my shotgun so I can see what the hell I'm shooting at in the middle of the night should I ever need to use it. I'm a cheapskate, and some of these lights are pretty expensive on their own, let alone the mounts for them, and my shotgun doesn't have any kind of rails. So I'm wondering, what can you guys recommend for someone on a REALLY low budget? I suppose I could always just rig a AA maglight to a hose clamp around the barrel, but I don't wanna go THAT cheap.

There are a few companies that make a flashlight that replaces the magazine cap, and I really like that idea in terms of maneuverability over having extra stuff hanging down or off to the side. But knowing that 20 gauge and 12 gauge are different diameters, I'm assuming the magazine tube and therefore magazine tube cap sizes are also different diameters, which means one of those lights isn't gonna work for me. Can anyone confirm or deny compatibility of magazine caps? Or is there anything out there that's similarly convenient and not crazy expensive(I saw some of these for 50 bucks) that WILL work on a 20 gauge 870? I also saw some forend replacements with lights built into them, but I have similar concerns there, and they're a little more pricey.