I am not aware of any other hobby where it takes as long to get products as it does with the muzzleloader parts production industry.
I’ll bet if someone ordered a custom-built race car just like the one that won the last Indy 500 it would be finished, shipped, and parked in their garage in less time than it takes to get a finished gun ( or even a complete UNASSEMBLED parts set ) from Chambers or TVM and other suppliers.
And don’t even get me started on The Rifle Shoppe.
These places have multiple employees and stock duplicators, too.
I understand not wanting to have a huge amount of time and money tied up in parts, but most of these places pretty much know how many stocks, barrels, locks and parts, etc. that they are going to sell over the course of a year, especially the more popular items. Maybe they are undercapitalized and operate on shoestring budgets or something.
Looks like they would be concerned over all the business they lose by not keeping anything in stock, causing a lot of potential customers to buy lesser quality factory guns, or used custom ones when they can be found.