Well lessee.
Black Max is good stuff, the added rubber contributes shock resistance which can be a problem with cyanoacrylates. Manufacturer's data sheet
Here. I use it to secure shotgun beads where there's not a lot of force with the itty-bitty things but plenty of shock.
Sheer strength is given as 3,770 PSI and tensile as 2,700 PSI. Note the heat degradation table, you can loose appreciable strength as the barrel gets hot.
Couldn't find a data sheet for JB Weld but they give tensile strength as 3,960 PSI and a "tensile lap sheer strength" of 1,040 PSI. Don't know if you can compare that directly with the Black Max figure. I couldn't find temperature derating info. JB Weld is supposed to be a high temperature epoxy but you know it's there.
Brownell's lists their Hi-Force 44 solder flowing at about 475F at 14,000 to 28,000 PSI tensile. They list their Hi-Force Hi-Temp 44 which flows at 650F (still easy to work with) at 38,000 PSI. For comparison 50/50 tin/lead solder has a tensile strength of around 6,000 PSI.
Silver solder has been the gold standard. Silvaloy 355 silver solder flows at 1,205F so it's hard to work with. Tensile strength is very much stronger.
How strong is strong enough I don't know, but I'd be wary of glues particularly if the bond isn't perfect.
Soldering, or sweating as used to join sight ramps, is an art learned by practice. Flux can be controlled if done carefully.
