The coolest part is knowing what something is, when the dealer doesn't have a clue. I got the light and the battery box two years apart from the same catalog. They didn't know that the two went together, or what it was used on.
My latest gunsmithing project just finished up, after considerable bloodshed (my own).
It started out as a "simple installation" of an aluminum quad rail handguard, according to the Brownell's description.
The Midwest Industries handguard was nicely made, but for some reason did not want to fit. I started filing on the front end, where the handguard slips inside the front cap, just behind the sight. More and more grinding (a combination of disk sander, Foredom hand grinder, and hand files) brought the thing closer to fitting.
When it almost fit, my hand slipped, and I raked the top of my tumb against the rail on the receiver. I wrapped my thumb up in a paper towel, and it stopped bleeding after a few minutes. I went back to work, my hand slipped again, and I raked the same spot on my thub, taking out a chunk of meat.
While healing up, I revisited the Brownell's site. This time, the description added, "does not fit Colt uppers". I knew that if I bled less, and filed more, I could make the thing work.
While browsing the site, two new items caught my eye. First was a new tool designed to let you work on AR15 uppers (and their handguards) without having it attached to the lower receiver. Second was a new product by Midwest Industries, a "free float" hand guard that only required cutting off the delta ring, rather than removing the entire barrel, as earlier "free floats" did. Barrel removal is about the only gunsmithing task I don't want to tackle. Cutting off the delta ring, however, would be a piece of cake after what I had already gone through.
The new tool worked like a charm, and allowed me to "mop up" the original project with little delay, and no more bleeding. I now had a handguard that would fit a Colt upper receiver.
With the tool in the vise horizontally, it was easy to cut most of the way through the delta ring with a cutoff tool in the Foredom. Then I stuck the tip of a large screwdriver in the slot, gave a twist, and the ring split in two. A bit more work with the wave washer and split ring, and I had a nice sturdy barrel extension ready to go. The new handguard was solidly clamped to the extension, while the rest of it "floated" free. It's rock-solid, and now nothing touches that barrel that could change the point of impact.
Here's the AR15 now, with about 20 yards of plastic rail protectors (to protect me, not the rails, which seem to do a good job of protecting themselves). I'm not sure Eugene Stoner would recognize his brainchild today.
The rifle now has a single-point sling, and a Pentagon 9 volt xenon light along with the Armson ACOG. And I have more than enough "rail real estate" to hang other stuff on. Although it does look a little odd from the top view, too.
The original aluminum handguard, now guaranteed to fit Colt upper receivers, will be going to a good home.