I have an older Remington 870 Wingmaster with the 30 inch full choke smooth barrel(not a vent rib). The bead is broken off. What front bead can I put on it? thanks ><> del
If a small-enough drill bit is used with care, the core of the broken stem can be drilled through it's center and the threads picked out of the threaded hole in the barrel top.
There are a plethora of replacement beads available with the proper size stem threads - including a bright fiber-optic.
You may have to drill it out and just bugger the threads, then re-tap the threads with the next larger size. Like Petah said, lots of beads available in various thread sizes - you'll just have to up to a bigger post/thread size.