I've had a Henry HO10 .45-70 GVT for a few years now. Hadn't done much shooting with it until recently. Whilst working up a hardcast load that turned out to be pretty stout (not intentionally), I noticed a ring in the chamber which I can't say I was really aware of before. I guess I've spent more time examining the bore and various parts other than the chamber whilst cleaning. And perhaps just not thought there should be any issues in there. And there weren't until this load. The first batch didn't give me trouble. It was only 5 rounds. The second batch of 20 gave me a couple sticky extractions. That's when I decided to clean it a bit better than just a brush and a bore snake, and noticed some sort of ring. I should have paid more attention, but I didn't. The next 20 rounds of the same hardcast load produced some very stiff extractions. I could see a ring mark on the brass. So I took some pics. I marked the case where the ring is, so I could get an idea of how far into the chamber it was. Despite not using any wads for any loads (though I had talked about it on another thread), here is this ring. It didn't cause extraction issues with some lighter loads I shot after the last 20 of that hardcast load. Those just popped out as normal. So my initial thought here was that this load is too much and I have caused the ring in the chamber by using it. But then I found a few boxes of empty brass that I hadn't cleaned. The first box of Hornady 325 FTX that I ever put through the rifle. A second newer box of the same that I had used to sight in with when I installed new sights. And a half box of empties of Buffalo Bore Magnum 350gr JFP that I couldn't shoot more of because they hurt too much. All of these where shot before I started working up this hardcast load, and all have a faint ring on them in the same place. Which means the ring was likely there from the beginning and I was just too ignorant to notice it for what it was. So there's now another possibility with the sticky extraction. All the brass I've used for this load workup is Starline. It was original from some cowboy load that I bought 5 boxes of online. I've just been cycling through this used brass for various loads so it's been getting some real wear. In fact the only time I recall loading new .45-70 brass was 20 rounds of this hardcast load which I was going to use as field carry ammo (so I haven't shot it yet). All others have been using progressively weaker brass, and that seems like it might be part of the problem. So before I contact Henry, I'm going to shoot some more Hornady 325gr FTX and see how it extracts. If it goes well, I'll try the BB Magnums and see how they extract. If that goes well, I'll try my hardcast load with the new brass and see how those extracts. Depending on how that goes, I'll have to make a decision about what I really want to do. Of course, there is the possibility that this new load really is just too much, and I do need to back it off. I guess I'll find that out next week.