Left hand threaded drum/bolster

[trackpin]

I was working on an Euroarms of America, Winchester ,Va, kentuckian pistol barrel in percussion. An NOS barrel that had an odd bolster /drum that I wanted to replace with a standard drum or touch hole liner. I tried removing it as usual, no rust involved and it snapped off. I just now drilled it for the easy out and the drill bound up a little and it unscrewed. I have never before ran into left hand threads on any type of gun part. Made in Italy. Why would they do that?! The breech plug was right hand as usual.

 

[Phil Coffins]

Winchester model 12 has a left hand treaded screw in the trigger group, for a good reason. I know of nothing else that requires this.

 

[Sam squanch]

I had an Italian 45 caliber single shot target pistol . The “patent breech” was actually a drum. It had left hand threads so it would tighten with each hammer blow.

 

[trackpin]

I had an Italian 45 caliber single shot target pistol . The “patent breech” was actually a drum. It had left hand threads so it would tighten with each hammer blow.

That makes sense, I can see how it would not loosen as the nipple was off center to the rear a tiny bit in the direction that blows would act to tighten it. An odd configuration, the part was zinc plated and at first glance would appear die-cast, the old ads for the pistol state it has a built-in flash guard, which it was.