I couldn't find anything via search, so I figured I'd start a topic.

The classic "rule of 6" has a few problems which I have resolved, at least to my satisfaction. As you probably know, there is no real difference between TN = 6 and TN = 7. I started with changing the "rule of 6" to adding only 5 instead of 6 to all re-rolls. That way, if you roll a 6, the second roll will result in a final roll in the range of 6-11 instead of 7-12. This applies to all re-rolls. Another roll of 6 will add 10, so the 3rd roll will be 11-16, etcetera.

This worked for a while, but considering the infrequency of rolling a 6, I further modified it to smooth the curve a little bit. I mean, if you graph it out, the probability curve "stair-steps" something wicked. I fixed this by re-rolling on 5 and 6, and adding 4.

Sure, there may be a little more wrist action, but the odds work much better as far as I'm concerned. The curve is smoother, but in the same general shape. I don't have the exact numbers at the moment, but if I have some free time, I'll crunch 'em and post 'em here for illustration.

Of course, you could just switch to SR4.... when it hits the shelves