Over the years I have heard that they are not good, on the chatlines alot of people want to curse and spit when .22 Thunderbolts are brought up. I have used them, but found the accuracy was second rate, ok for cheap plinking. During the Spring of 2009 ammo was in such short supply that I bought a brick of them, as one of my Ruger 10/22's likes them. Seems like I was getting some out of battery fire on my other 10/22, so did not restock. Especially now that ammo is more available.
There was a guy on You Tube who was getting severe leading build up in his Ruger Mk. 2 pistol, and made me more cautious about using them, I occasionally clean the barrels on my rimfires, so maybe he needed to do that with that load. Anyone else have problems with Remington Thunderbolts?