Does new brass need to be "resized"?

[Dusty Miller]

My new .45 ACP brass arrived measuring 1.263" but I ran one thru my resizing die and it came out 1.265"  Is this an important difference?  If so, shouldn't my new brass all be "resized"?  I'm thinking that the volume of the case is altered by resizing and if I want all my pressures to be the same then the new cases should be ru thru the sizing die.  No?

[Val]

I always resize my new brass for the sake of consistancy. From all the handling from factory to retailer I find many of the neck openings to be dented or out of round so they need sizing to round out the openings.

[KN]

If its a straight walled cartridge you may be able to just run the flaring die and it will straighten out any dents or out of round condition. If its a bottleneck cartridge then yes I always resize new brass to insure that it will chamber correctly. You don't want to load a box of brand new shells and find out the body is too tight for your gun. It will ruin your day.   KN

[Iowegan]

I always resize new brass then trim the mouth just enough to "square" it. With rimmed pistol cases, I like to trim all cases to a uniform length so roll crimping will be more precise. The last batch of RP brass was really bad. I had to toss 12 out of 100 because of split case mouths. If you don't feel it's necessary to resize, then at least give the brass a thorough inspection.

[New Hampshire]

I recently bought some .45 colt brass.  Out of curiosity I took a .45 cal bullet I had and was able to hand seat said bullet with very little effort.  I always size new cases, and this just shows why.
Brian M.

[1911WB]

I inspect new brass for obvious defects. If it has none or if mouths are only slightly dinged in shipment, I merely bell them & move on in the process.  :-)

[Donna]

Iowegan wrote:

I always resize new brass then trim the mouth just enough to "square" it. With rimmed pistol cases, I like to trim all cases to a uniform length so roll crimping will be more precise. The last batch of RP brass was really bad. I had to toss 12 out of 100 because of split case mouths. If you don't feel it's necessary to resize, then at least give the brass a thorough inspection.

Dusty Miller,

Seeing though you’re using an ACP remember not to use a roll crimp, you can use a light taper crimp just to take out the bell or balling from the case mouth. If you did not know: all ACP’s seat on the case mouth and a roll crimp will not allow the case to seat properly. If you did know my apologies.

Donna

[Iowegan]

Donna, Duh? can't you read either? "With rimmed pistol cases, I like to trim all cases to a uniform length so roll crimping will be more precise."

Read rimmed cases. I'm getting tired of you finding fault with everyone that posts a reply. If you can't read and comprehend the contents, then don't make stupid comments.

[Duffy]

As Brian M found out most 45 LC cases are a bit large and need to be sized before use. I think they are still hung up on the old .454 diam.
Dusty, when you size brass it has to go somewhere, that's why it got longer. That little bit isn't going to make a difference as long as there isn't big differences between cases. Load some up and shoot them and see how short they get before you size them again!

Ryan