I haven't seen the the slow blow wire move, but I have seen the
.5 - 5. amp fast blow, bend. I don't run amps that require above 6-8 amp surge on startup.
I had one going through fuses too, 3-4 times a year. Everything in that amp was better than new, except a filter cap was acting up, one day it sprung a leak.. YUP like an ol Harley, I changed all 4 caps, hasn't blown a fuse sense. BTW they were just replaces, just a bad one, in the bunch, Cary took all 4 back and replaced at no charge, and paid the postage..
The fuse your looking at, is not how SR fuses are made. They don't fail like the one in the middle and on the right. Both those fuse will sound bad. The new one will sound good until it looks like the one in the middle. Different construct all together than SR fuses. Many of the other fancy fuses are different than a Busman in "HOW" they are made, it's not just what the end caps are made of or the fuse wire, its how and what it's made out of and that GOO they put on it...
They are different... How they sound, and how they are made...
Apples, Oranges!!
Regards