I've beat on them too. Generally when you shear a pin, it's because the cones are worn and are not locking up like they should and you end up with some 'one wheel peel' and when that happens, chances are it's going to gall a spider to the cross shaft and shear the pin. When you end up with just one tire spinning, most think that if they get on it hard enough, it'll make it lock up but it won't. It'll just self destruct. Several years back, a buddy was running a 70 440 Challenger RT at the track with a cone unit turning low 11's and I 'tightened' it up some and told him at the first hint of one slick not turning to pull it out and I would go through it again but do NOT try to make it lock because it won't. It was many years before he brought it back to me. It was still in good shape as far as the pin was concerned and all I had to do was machine the cone's faces and add some shims. That was 10+ years ago.
Over the years whenever I got a cone unit, I just put it aside for me and sold the clutch types because everyone thinks the cone units are junk so I got more money for the clutch units. Several years ago, someone gave me a cone unit and the thing still looks brand new inside! Yeah, the clutch units are very good but I've seen plenty of those that looked like scrap inside too. Thing is, you can buy replacement parts for them if needed but people seem to know how to trash anything no matter how good it is. Btw, I've never killed a cone type SureGrip and if you knew me, you'd call me a liar just because of how I've treated most of my cars. Most that don't know me well have asked how many times have I rebuilt the trans, rear end or engine. Half the time, I don't believe how the stuff holds up either! lol.