Anyone know where to buy cardboard mortar tubes for 1.75" shells?

[Fox One]

I am going to need a large quantity of new mortar tubes (several hundred) for a project I have in mind and I'm probably not going to be able to afford enough HDPE or fiberglass tubes fast enough to meet my timeline. Does anyone know of a source for cardboard mortar tubes? I'd prefer them with a base since I'm gonna use them on poor man's racks, but it isn't a must. I think I've found a source for inexpensive bases if I need them. But the tubes themselves seem to be very hard to come by. I found one fireworks related site that does sell them, but they are currently out of stock on everything.

[Kenny East]

Out side of shell kits,cardboard tubes usually cost as much as fiberglass.... Other option,roll your own from Kraft paper... But that's a lot of time.

I know a retailer that sells cardboard with bases but for the price bulk fiberglass is a better option. And fiberglass gives you more options on what you can shoot out of them.