The only cock on closing rifle I have is my Enfield. If you take modern cock on opening rifles like the Remington 700, and the Winchester Model 70, it really doesn't take any added effort in lifting the bolt handle to cock it. You can easily do it with just your thumb. There is plenty of camming action to do both cock the firing pin, and extract the case. Even with hot loads. I never cared for cock on closing. It just seems awkward. Especially if you have a scope mounted with not a lot of bolt handle clearance. With cock on opening, closing the action on a live round is effortless. Even with controlled round feed.