Sizing New Unfired Brass?

[PLX65]

What is the thought about sizing new unfired brass? It makes sense to have your brass uniform, but is it really necessary?

 

[Mac679]

It repairs dented case mouths that can occur during shipping.

 

[Supersubes]

What’s important is that you get the necks to the size you want. Virgin brass can have a very small ID, and minimal inside chamfer. A mandrel comes in handy for this. Your die won’t even touch the body, and unless absolutely necessary, don’t bump the shoulders any.

 

[Strykervet]

What’s important is that you get the necks to the size you want. Virgin brass can have a very small ID, and minimal inside chamfer. A mandrel comes in handy for this. Your die won’t even touch the body, and unless absolutely necessary, don’t bump the shoulders any.

I HAD to do this with Laupa brass, turns out the .308 is the tightest. Damn near strips the copper off. The mandrels are cheap and if you use a Dillon trimmer it'll negate the need for a sizing die altogether (for most common calibers). Once you fire it, if you use that brass in only that rifle you only wanna size the necks because it'll be fit to that chamber.

I've heard of people sizing new brass but I never have. If they look good in a gauge they get loaded. I may resize used, sized brass though.

 

[spife7980]

I anneal and then run them over a mandrel first in hopes that it leads to more consistent tension and in turn shoulder positions when fired. It sure doesn’t hurt.

 

[Codiekfx400]

I have always full length sized new brass right out of the bag no lube. I have never had a stuck case doing this but the inside of the case mouth gets some minor finish scratches. Does anyone think these minor finish scratches are hurting my accuracy on target?

 

[supercorndogs]

I doubt much of your new brass is touching the inside of the die. Just round out the mouths and fire form them. Then you are ready to set up your die, and start load development.