Just a general note abotu sizing rimmed and other cartridges. Be careful when sizing not to touch the shoulder unless you absolutely have to, to get them to re-chamber. Try sizing the case in the FL die so only 3/4ers of the neck is sized. That way, the shoudler will not be touched. If that fired and resized case chambers easily, then you only have to partial fl size - some call it neck sizing with a fl die.

The .303's very sloping sides will promote case stretching, which can be held to a mimimum with partical necks sizing. The cases don't stretch at the shoulder, they stretch at the web, each time they are fired if the shoulder does not fit the chamber properly.

In other words, if the shoulder is pushed back each time they are loaded, they will not last long before head separations occur.

The overly long bodies found in many military rifles was the reason for my hoping the Rugers had 'tighter' chambers. The throat means little.

If you want to crimp, any bullet can be crimped on the smooth portion of it's shank, if you use a Lee Factory Crimp die.