Teflon tape ?

[Unclenick]

Back in the early '90s, some Teflon-bearing lubes and greases were sold to treat bores for jacketed bullet shooting. The problem was chlorofluorocarbon properties change a bit as they heat up, so rifle groups wandered during matches, particularly in rapid fire. Friction Block was one of the products, and I think S&W acquired them or at least bought branded products from the maker. Those products worked fine for other gun mechanicals but just weren't able to produce consistent accuracy when they were embedded in the bore and weren't easy to remove from a bore later completely. After a time, these products vanished, and the much more temperature-tolerant moly and hBN bullet coatings replaced them.

Generally, cast bullets are run at lower pressures and temperatures than jacketed bullets, so Teflon may be OK with them, especially if you aren't shooting at a fast pace. But, personally, I don't want to get them in a bore because of the removal issue.

[Bazoo]

In the book: The Winchester Lever Legacy, Clyde "Snooky" Williamson goes into detail about teflon patching bullets. He patched bullets in conjunction with lube, and got better accuracy from his report.

There was an article about it the a book called: The Art of Bullet Casting, which was reprints of Handloading Magazine's articles. I don't remember who wrote the article.