Shaving lead is definitely a timing issue on the magazine
Sounds to me like a filthy gun needs to be cleaned inside and out thoroughly inspected for headspace issues and parts that may not be surface true. Ex breach of the barrel and face of the magazine.
I don’t like 51° weather, but yeah...
No it should not do that.. rifle may need a good cleaning inside and out and a thorough inspection
Question since you bought the rifle has it been doing this the entire time you have owned it?
I own several of the rattlers and Sidewinders bought them new. When I seen your post, it reminded me of the 30 caliber that I bought. And from the factory the brackets that hold the barrel from rotating was not tightened all the way down so over a few shots the barrel started rubbing the face of...
I see.. yes, I was thinking it was a headspace problem, but with what you just described you might have to send in for some warranty work.
I wish you well sorry I wasn’t more help