Hades. If you have found a Remington 7400 in 30-30, buy it. It is one of a kind and priceless. Seriously though, double check the caliber. I'll bet it it either .308 Win. or 30-06, if it is a 30 caliber of any kind. From what I can tell, the 7400 comes in .243 Win., .270 Win. .280 Rem.,30-06, and .308 Win. Nary a thutty-thutty in the bunch.
Longhair. Most of the time when a Remington semi-auto rips rims off the casings, it is dur to a dirty or rusted chamber. keeping it scrupiouly clean should alleviate the problem.
Paul B.