butchlambert
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I use my drill motor with a bronze brush in the throat for about 5 seconds after chambering. Mine ain't got those marks. I really don't see those marks in the photos as brush marks.
I let Lucky Shooter borrow my brand new reamer. RPM he used was 70. Dark sulphur cutting fluid.
I have never seen this in one of my chambers...mind blower for sure.
Many thanks for many ideas-----still puzzled here.
Well GGmac, no stranger to impolite here----cut'er loose baby or just sent me a PM.
Would love to hear what you think.
I hope you didn't mind me putting your pics on here there is wealthof knowledge from the old timers.
A. Weldy
Not those scratches. A tool did thatIs there any chance the bronze brush was made with core of twisted steel wire? The twisted wire at the front end of the brush could scratch the chamber.
Question what kind of barrel.Here is a picture.
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Shilen 14 twist.Question what kind of barrel.
If that's the case on the edge like it is I think they didn't get rid of the reamer marks when they lapped I wouldn't be overly concerned.Shilen 14 twist.
This was done during chambering. All of us that do this for a living pay special attention to the surface finish on the lead angle in the throat. That area of the reamer is the single most important cutting surface on the entire reamer. Not all reamers will yield the same surface finish. I retire reamers as soon as I see that cutting edge breaking down. That can happen quickly depending on if and how you rough in a chamber. I go so far as to polish the throat in all the barrels I chamber.Is there any chance the bronze brush was made with core of twisted steel wire? The twisted wire at the front end of the brush could scratch the chamber.
How many rounds on that barrel? What's the location of the photo? What's the other end of the barrel look like? It's difficult to tell but it appears to be heat checking with copper in the cracks. I don't see any symmetry to the pattern and I don't think you could get as vivid a reflection from just tool marks in a used barrel.Here is a picture.
View attachment 1127692