by VICHunter » 12 Feb 2014, 2:20 pm
Both will work, with a few considerations... None of these are necessarily "problems" but depending on the performance you expect, or just maintaining best practices you may want to address them.
1) When necking down brass you're compressing more neck into less space, making the neck wall thicker.
The thicker neck may create an increase in neck tension on the bullet and give a different POI compared to factory brass.
Best practice would be to neck turn them like Chronos said so the neck walls are a consistent thickness. Once the necks are turned, for all intents and purposes you have 'factory' spec brass and it will be no different. It's not critical though.
Failing that, simply firing the cartridges will make the neck extend and thin, normalising the brass. With repeat firing and reloading the resized brass will just become part of the regular rotation of brass.
2) On the flip side, when necking up brass you're stretching the neck and it will thin. There would be no need to turn the necks and they'll already be more than thin enough. This too could result in a change in POI, compared to factory brass, but isn't an immediate concern.
The only real concern with necking up is that you're starting off with less neck, so the brass won't last as long before failing. You'll end up with split necks sooner compared to factory or necked down brass. Again, not critical, you'll just get a bit less bang-for-your-buck on a shots-per-brass basis.
Turning the necks in option 1) would be ideal, but any of the above will work in a pinch.