Garand said:
Because of the design of the .303 cartridge case, most casings are only good for about 5 reloads unless they have been used in a fully automatic firearm. Everyone who shoot a .303 should have a broken case extractor from brownells
www.brownells.com Don't screw around with substitutes, you could damage the bore.
The broken case extractor is an excellent idea if you reload any caliber, .
Case head separations can happen in just about any rifle with a large chamber or just a bit of headspace. And you can very easily damage the chamber or the bore using "other" methods.
Gun parts (Numrich arms) also has broken case extractors.
It is a myth that it is the design of the 303 case that causes case failures in reloads. Case failures in the 303 british are usually the result of very large chambres in military surplus firearms coupled with the rather generous headspace tolerances in production.
I have had 303 brass that would last just as long as 30/06 brass and 30/30 brass when reloaded carefully and shot out of a gun with a good chamber and tight headspace. Much depends on the way you resize the case, and the pressures you are loading to. I have also shot some 303s that would separate brass on the first or second reload.
I have a M10 Ross that has cycled the same brass through reloads over twenty shots with no case head separation issues, - part of the secret is to aneal the case neck, neck size, and use the same brass for the same gun.
The other gun writer myth is that the action of the No.4 "stretches" on each shot. It may well, but it isn't as critical as chambre size and headspace. In fact the No. 4 rifles that I have are at minimum headspace and brass lasts at least ten to fifteen shots, way more with cast bullets and pistol powder.
Neck sizing and not using maximum loads do make a diference.