If the rifle prefers a lighter bullet, especially one in the 140gn range find one that has a better, more solid construction. I like the Woodleigh 140gn Protected Point which is made in Australia but is available in the US. Using a well constructed bullet with reasonable velocity is a far better option than going to light bullets that probably won't penetrate. They may start out fast, but they also shed velocity a lot faster as the range increases.
