You beat me to modifying my reply. I seek platinum lined musket cap nipples 1/4-28 rather than #11 nipples that Buffalo Arms has available.
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Following up the original query, because of its incredibly high resistance to heat erosion, plus its significantly improved longevity in use, platinum lined nipples are not nearly as overpriced as one might believe at first glance. And were the shooter wanting to push his rifle to its maximum potential, such nipples become a valid choice - not necessarily the choice, though.
Among factors not usually considered are: "Maximum" load development can be time consuming and stressful on consumables. Problems, slight as they might be, can occur when one develops a nearly perfect load, but that perfection disappears when the nipple quickly deteriorates under the additional stress caused by huge charges - that is, battering from repeated impacts and flash hole becoming enlarged by heat erosion.
Were such loads not something wanted or needed, the additional expense of such high performance nipples is probably a waste of resources.
Just some thoughts.