If you are resizing brass for a break open H&R you will have to full length resize the brass. There is enough give in the action so that the brass will be too long to close the action on a fired case. Try putting a fired case back in the gun and see if you can close the action, if not, then neck sizing only will not work for you. A H&R in 270 is about the limit of pressure for that gun. It is hard to pull down the sizing lever because the die has to push the sholder back so far. Larry