also what the hell do you mean "make your own flashlight"?
I can't speak for him, but most Surefire pattern lights are modular, and can be assembled with bodies, heads (either complete with LED, or with a drop-in LED), and tailcap/switch, remote of your choice. You'd have to look at companies that sell individual parts like Arisaka, Malkoff, Z-bolt, Lumens Factory, etc, and mix and match what you want. I'll say again, Arisaka/Malkoff make slim and bright scout heads that look good.
What are some good options for glock barrels?
Brownells house brand barrels are good to excellent, and also around $100. I also like that they don't have exposed logos, unnecessary milling on the hood, or fluting that makes the barrel worse. They drop right in and eat everything. I wouldn't get anything cheaper than that.
Rosco has a deep sale on Glock barrels right now.
The KKM that I had, had a tight-ish chamber, but was picky about ammo it would chamber. Accuracy wasn't all that great either.
I had a
FJ Fedderson, but it wouldn't take my handloads with 124 JHP bullets (short throat) so I sent it back.
Triarc Systems barrels are made by FJ Fedderson, so they have the same short throat problem, and fuck that noise altogether.
Barsto has been one of the go-to companies for high quality barrels for years. Whatever you decide to get though, make sure you check to see if it is a drop-in barrel that requires no fitting or gunsmithing, or if it will be requiring fitting by a gunsmith.
Barsto are all either semi-drop-in (needs some work), or gunsmith barrels (NEEDS LOTS of work), expensive, and I don't know if they sell threaded barrels.