I can tell you, I have done more and faster than that at some double rifle shoots.
I never thought it to be a problem but the barrels do get pretty darn hot - too hot to wrap your hand around, that's for sure.
Normally, doubles are heated to high temps when regulating and I don't know if they are allowed to completely cool between pairs. The heat to melt the solder is way higher than rapid shooting will produce so my bet is that it's just fine.