Lee Loader

This question is about how small should a die squeeze the case to. This is just a generic question for all calibers. Lets say we are loading a .303 British. The bullets are .312" diameter. The expander is .310". How small should the die make the brass .306"- .308" before the expander opens it back up to .310"?

I have a set of dies that is going all the way down to .298". I think it is over working the brass and in some cases crushing it some to have run out in the brass. Wall thickness varies .001".

Thanks Ricky

Yep that's overworking the brass some .303-.305 would be better . If you have access you might try a 300 WSM for neck sizing . I have a 30-30 with full body dimensions and use a 308 sizer to neck size the thinner brass and larger neck dia in the die only sizes down to .306 for loading .309 paper patched and .310 cast . I think a WSM die would do the same for the 303 .

As a more permanent solution the die can be lapped larger . I've read about it but never done it as I have many alternative dies to try where needed.

I work at a machine shop so I can get it opened up. I went ahead and got an older set of dies and they are sjzing dowm to .308".

In theory the sizing die should return the case to the SAAMI specs and if properly adjusted most do the job. Then there are the out lyers. If that's a new die I think I'd have a speak with the manufacturer.

Make smoke,