You guys are reading the caliper wrong. The case is .002, which is 2 thousandths, longer after being sized than it was before, which is pretty insignificant and probably the result of squeezing the case body and dragging the expander ball out of the case neck. The fourth digit after the decimal is 1/10,000 and will either read 0 or 5 which is 1/2 a ‘tenth’ which is completely insignificant when case forming.
Turn the sizing die in 1/4 turn and re-measure. Keep turning it in until you get to -0.0030 which is 3 thousandths less than the fired case dimension.
Unless you are using a very light load, the 30-30 case is fire forming to your chamber. Take a look at this which shows the case forming taking place when converting 30-30 to 7-30 Waters. The pressure is not much different than 30-30. It is really cool to see the difference in case shape before and after pulling the trigger.
https://www.clarionledger.com/story/outdoorsreport/2014/11/10/7-30-waters-not-dead/18792283/