Re the 140 grain Remington bullet: I believe these are the two diameter bullets, made for the original .264 Winchester. I have a box from Midway, repackaged, and I just measured the diameter behind the cannelures at .264 but forward of the forward cannelure the diameter is smaller, about .259. These bullets don't shoot very well in either of my 2 6.5x55s either.
Re the Winchester Model 70 FWTs: My push feed has a really long throat and prefers long bullets. The more recent CRF Classic has a much shorter throat and shoots fine with 129 grain Hornadys. Before you load for one of these rifles you should find out how long the throat is. The old rules about overall cartidge length may not apply anymore. And the Mod 70s used the long action for the 6.5x55.