Endoscope pics of different breeches

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Jul 6, 2021
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Hilton Head, SC
Decided to take and post pictures of a few breeches in the guns I own. Hopefully it will help explain and understand discussions regarding issues we have with our beloved guns. I’ll post the description of the gun and in sequential order my observations.

1. 50 cal smooth bore, English breech
2. 58 cal. Navy Arms Musket barrel, flat breech.
3. Green Mountain 40 cal., a Tapered patent breech, notice narrow face of breech plug and tapered walls.
4. 40 cal Flintlock, flat breech.
5. Hatfield Patent breech (Ante chamber) notice straight narrow walls of breech.
6. Barrel in. Marvin Crandall 45 cal, tapered patent breech, circa 1850–1887.
7. 1863 Springfield 58 cal Musket, Flat Breech
8. Green mountain 50 cal., tapered patent breech.
The best way I have found to clean these is flushing hot water with Dawn, then flushing with hot clean water. However, finding a small bronze brush with a cleaning patch applied to scrub the patent channel is advised. The Hatfield is without a doubt the most difficult to clean.
If you have had misfires, figuring out how to clean this part of your ML can be a challenge. UntilI got this scope, I didn’t fully understand the cleaning process fully. Hope this helps!


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Jul 6, 2021
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Hilton Head, SC
Those sub-caliber breeches are just no fun at all. I'll not own another. I'm seriously considering selling my GPR and Pedersoli Kentucky for that reason.
I’m told the Pedersoli patent breech is the same as my Hatfield. I use a 22 cal. Brush with a patch and cleaner to scrub it out. I also go in through the clean out screw and nipple area with a pipe cleaner. Haven’t had a misfire since.

Notchy Bob

58 Cal.
Apr 6, 2014
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Thanks to all who posted photos and drawings. This is very enlightening.

Thompson/Center used to make a special breech scraper that would fit in the powder well or chamber of the breech plugs for all of their guns. It had a rounded end to match the chamber. I haven't measured one, but I would estimate these to be about 5/16" in diameter.

These chambered breeches can be a challenge to clean, but it can be done. The hardest rifle to clean that I've ever owned was a nice built-to-order Lancaster-styled flintlock by a well-known custom builder. This rifle had a 7/8" by .50 caliber barrel. Despite the fact that I requested no vent liner, the builder put one in anyway. This was a White Lightnin' liner with the countersunk head. He left it full length, protruding into the bore. This created sort of a "double whammy," a fouling trap that was very difficult to clean. You could not get a jag, wiper, or breech face scraper past it. Otherwise, this was a pretty nice rifle, but I let it go. The aggravation of cleaning it was one of the reasons. I was not equipped to deal with the protruding liner myself, and no gunsmith wanted to touch it.

Best regards,

Notchy Bob
Aug 14, 2022
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My Heavens that’s clean!
I wish the bore was that perfect. When I got it, it had patches of rust throughout the bore. I used rust remover CAREFULLY so as not to remove any bluing on the outside. But patches of pits still remain. I have scrubbed it clean, polished it the best that I can (I don't feel any tight or rough spots) and just going to live with it.

It hadn't appeared to be shot much, just not stored properly.

Same breech with a better view of the hole drilled into the breech for the flash channel.
On the bottom at 5 0'clock
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