Blown out shoulders and the .303

20160304_181700
What a beauty!

Back in the days of yore, good old boys carried the Lee Enfield into our wars. I love my Enfield. It is an accurate rifle, light handling, powerful and pretty. That’s all a man needs in a gun, really.

Being a reloader, I thought I should reload for my Enfield. There are a variety of die kits for the .303, and I bought the Lee Loader kit.

20160311_154216
The dipper is quite useless.

Here it is. I like Lee Dies.

If I were to compare it to RCBS dies, I would say that the lock ring with the gasket is as secure as the RCBS dies, just without a small set screw that rounds out as soon as I use it…

The main feature of this set is that it is a neck-sizing die, not a case sizing die. With the .303 this really matters. When Enfield designed this cartridge/rifle combo back at the turn of the last century, (think 1890s-1900) they designed the cartridge to seat on the rim. It is a rimmed cartridge, after all. An example of the modern method of seating the cartridge on the shoulder was adopted by the Americans in  the 1903 Springfield in .30-06.

Because the .303 cartridge is seated on the rim, head spacing isn’t as critical to the performance of the rifle as in shoulder seated types. The Enfield designers thus left headspace tolerances wide open. If a rifle suffered from too much headspace, the armorer could swap different thicker bolt heads in or out as the case needed. In a service rifle, this isn’t a catastrophic design flaw. Its just a workaround that works.

20160304_182142
observe the blown out shoulder on the once-fired brass, and the overall case streching

This is what my rifle does to casings. I actually swapped out the original bolt for another one on account of brass that was tearing just above the rim.

The shoulder on the factory load (Winchester Super X) on the right measures 1.784″ from the rim to where the shoulder begins. On the once-fired brass on the left (PPU) the same measurement is 1.843″. Notice the shape of the brass shoulder also changes. In the fired cartridge it takes on a rounder profile.

The Lee loader is a neck-sizing die. This means that the whole case isn’t resized, just the neck down to the top of the shoulder. Because the case stretches significantly, 0.059″ in my rifle, a full-length die would have too much material to push. This would lead to case deformation. The neck is really the only part of the case that requires resizing anyway. Remember, this cartridge seats on the rim, not the shoulder.

There are a few things to consider when reloading the .303. First, no used brass can be guaranteed to work in any rifle other than the one it was first fired in. Enfields have some pretty random interior dimensions. Second, beware of case-head separation. That brass stretches quite a bit. If there is excessive head space it will rip the casing, and could damage your rifle or lead to extraction problems. In this case, get a new bolt or bolt head. Third, be careful how much powder you load in the used casing. Once fired casings have more capacity than the factory brass. Overfilling can happen, and if it does you then have a safety issue. Blowing up old guns is not my idea of a good time.