I need your opinions. I recently bought a new Weatherby PA-459 in 20 ga. Fired 50 rounds of 2 3/4" bird shot with out issue, and I have to say, I love this gun. I then put 20 rounds of Win/Olin, 2 3/4", 7/8 oz, foster type slugs through it sighting in the irons. Starting out with a mirror clean bore. Those 20 rounds completely leaded the bore from the chamber to more than 2/3 to the muzzle. I mean completely coated the bore with lead. It was so bad the lead was coming out in chunks, and it took me three days of soaking and scrubbing to get it out. I've never seen any thing like it. I'm of the opinion that it can only have been caused by one of two things. Faulty/poor quality slugs, or an over sized bore. Myself and many people I know have been shooting Winchester foster type slugs since the dawn of time with never an issue. I also realize that some streaking or minor leading with slugs is to be expected. But not like this. Any ideas? I will be calling Weatherby customer service and see what they have to say also. Thanks in advance for any replies, ideas, opinions, advice, or just plain general banter.
Dave.