My 10/22 would eat it just fine and I shot hundreds at a time back in the early 90s. I would say its a lube issue from certain lots or maybe under sized bullets. You have to have some sizing issues between barrel and bullet to pull that kinda lead. Basically the bullet is not spinning but being scraped straight through. I had some under sized 9mm that would do that in my XD9 to the point one mag would make the rifling disappear, but yet my RO 9mm was very accurate with it and very little leading. Also the guy that loaded this stuff back in the 90s, cooked it with a bit to much spice and a bit to much crimp. Its the only lead rounds I have ever shot that would every so often show pressure signs on the primer.
It is almost hard to believe that these Thunderbolts get through the bore once you hit the point a patch gets stuck that bad, but there isn't much space between a .22 bore and a cleaning rod.
A .17 caliber cleaning rod would be good to have for this situation with a tornado brush on it. Or stick to the plated stuff.
I remember back in the old days going to Roses and getting a 50 rd box of Wildcats for 50 cents or so. I would save my lunch money and have my grandmother take me over after school at least once a week to get 22s. CCI was the premium ammo back then. Stingers were the prize at $5 for a pretty blue box of nickel plated fun.
