Marks Inside Muzzle

I had sent following message on another forum, awhile ago:

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I have a Garand (SN 5.89) and today, when I checked it for cleaning, I noticed that the barrel had what appeared to be light (faint) circular machine marks inside the muzzle.
Closer inspection, I note that bore is clean as I left it last time, but for the life of me, I cannot recall these marks before. I bought the rifle from CMP some 12 years ago as Service Grade Springfield. The CMP tag simply has 'SA G-3' but the ME or TE numbers are not shown on any of the CMP paperwork. Rifling landings are crisp.
I shot the rifle only some 12 or so rounds, back when I got it and it hasn't been out of my control since. The rifle shot beautifully.
I would like to pose to you all what your thoughts might be on this, for I'm simply lost on what the marks are. They are NOT vertical in the barrel, but circular and parallel about 1/32" apart as if made by a machine. I can't see how far down the barrel the marks go since I don't have a bore light, but I can see they are down about an inch from crown. I don't see how the marks survived the firing since the marks are not deep at all. I'm quite certain they are not cleaning scratches for I use a nylon bore brush.
I would appreciate any thoughts or comments you might have and whether or not you have ever run into this, i.e. ream marks,, etc. Thanks.
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If anyone would have idea of these, I'd really appreciate your comments.
Thanks.
Player37

Perhaps from aggressive cleaning? Perhaps a machining flaw when it was made. Pictures would be ideal if you are able. If not, contact me in a PM and we'll exchange email addresses and I'll post them for you. :thup:

Reamer marks left before the rifling was cut.