Looking for some input, Hive.

I broke the bead off of my 1980s 870 Magnum and all that is left to grab onto is to close to the sight base to get any sort of grip. Would epoxying an XS Big Dot over the broken off bead work or am I asking for failure as it won’t have that point of contact to bond to?

It will probably be fine. Back when I used 870s I often used the XS big dots, the sight has a hole that you place onto the bead, but it also mates to the sight base as well. I’d rough up the remainder of the bead, and the area down the sight base where the XS sight sits, clean it up well and use JB weld, fill the hole in the XS sight with JB weld and the bottom of the big dot sight, use a clamp to hold it in place on the broken bead, clean up any excess weld that comes out from under the big dot. I’d also let it sit for a few days prior to using it since there will be more JB weld in that hole than normal it will probably need more time to harden properly.


This is from a few years ago when I built up a Tac-14 for a friend. You can see how the XS sight uses part of the base. You can see a little JB weld leaking out before I cleaned it up. He still uses that gun for patrol, he SBSed it. The JB weld has worked great and the sight has held up with no issues riding around in the rack of a police car for the past three years.
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I also installed a big dot sight on my 590 Shockwave using JB weld. No issues.
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Thanks for the detailed write up, I appreciate it. Do you recommend JB Weld over something like Loctite 380 Black Max?

Coin flip on JB versus Black Max.

In this application I'd probably use JB.
Tricks to a good bond...........
Thoroughly degrease everything, finish with a spray of denatured or 91% alcohol.
Warm with a hair dryer to dry and lightly warm the metal,  HAIR DRYER, not a torch or heat gun. that's way too hot.

Roughen up any surfaces you can to give the bonder a good "tooth" to bond to.
Get a good mix of the bonder.  Usually 50/50 and some people use a powder scale to weight the two components to insure a strong result.
MIX the components thoroughly.  Too many people give it a fast stir or two and use it.  The better the mixing the stronger it is.
I often mix longer term epoxies for at least two minutes.

Apply a coat of wax to every surface you DON'T want epoxy on and let the wax dry.  Shoe polish wax will do.
Don't wipe it off.

With the barrel and sight slightly warm apply the epoxy to both parts and clamp the sight on the barrel.
Let the epoxy cure to a soft rubber state and use a plastic or brass "knife" blade to cut the excess off.
This will prevent smearing epoxy on areas you don't want it if you try to wipe fresh epoxy off.

Put the barrel in a warm place and let cure at least 24 hours to reach full bond strength.

If this sounds overly complicated, I've found that the little things are usually the difference between a good job and something that fails.

This is the process I used on my 590A1 SBS over 15 years ago and it is still on there.

As stated in the excellent write up by the other poster, either is fine. I used JB Weld just because I am most familiar with it. I’d follow the instructions written up by the other poster and you shouldn’t have any issues even with the bead being partially gone.

Thank you for this!! I’m weighing right now contacting a gunsmith to see the cost of drilling and tapping the pedestal for a screw in bead as well.