Tuning Replacement burst/rupture disc for Nova Vista Freedom

I don't know how this happened, but I blew the 4500psi rupture disc on one of my Nova Vista Freedoms.

Apparently, the pressure gauge on the Freedom was stuck and I did not realize it. The strange thing is that I was pumping it up with an external hand pump (because the onboard pump was not working) and THAT gauge never made it to 3000psi, which is as high as I ever pump up the Freedoms. I am baffled why the 4500psi disc blew...

BTW, using the same hand pump, I have pumped up a Fortitude since this happened and the gauge on the hand pump worked fine. Go figure...

Anyway, can anyone tell me where I can find a replacement burst/rupture disc?

Thanks in advance!

Kerry