Does anyone have one of the rounded breech scrapers for Thompson Center rifles? If so, what is the width of it? I have a few scrapers and was figuring on bringing the edges on one down for my TC New Englander' breech.
I don't think that's the one you want, as the TCs have a dual-diameter or "Patent Breech". They used to make/sell a scraper that had both diameters, but they're tough to find in .50 cal although I do recall seeing some in .45 about 6 months ago on eBay. You can grind your own if you're handy.
Kudos' go to Idaholewis for this image of his cut-down TC breech which he'd posted back in 2019, as it clearly shows the patent breech and the flash channel. This will better show you while the dual-diameters is important.
When I had a TC Hawken, I'd use a .36 or .40 cal bore brush (in a .50 bore) to get it into that rounded part of the breech. Make sure you clean/blow out that flash channel too, or it can cause misfires.
I've seen these for years but have never felt the need for one. I started out in the 70's flushing with hot soapy water (now just warm) and have never had a problem with ignition. Perhaps there is gunk in there I don't know about but it's not causing any problems. Unless there is some caked on fouling from improper cleaning i've never seen the need for one. I've been wrong before.