Any words of wisdom?
This is on a model 120, where the receiver is soldered
at the factory to the pump tube (brass receiver & steel
pump tube) I think the Benji 310/312 are a similar deal.
What solder and process was used? That may determine
whether I attempt this repair.....
and its not that big of a deal.
The one things you need to look out for is annealing your brass; this is a BIG NO NO
Read up on annealing brass, before you heat your tube
DO NOT USE silver solder it requires too much heat.
You need to get on the heat and get off, top of my head I would say a low red heat is way too hot.
if you are wanting to repair the gun without complete disassembly use a solder containing bismuth, not as strong but makes a good repair, this will work at such a low temperature you can leave the valve in the gun with no damage.
When I first started to repair barrel tube separation I used 63/37 solder,
it melts evenly, has a specific melting temperature and wicks very well. I have never had a gun separate after a repair.
the best way is to completely disasemble the gun clean flux and give it new solder