Load development with brand new never shot brass?

[zr600]

Ok the other day I shot my 6.5 creedmoor with brand new Nosler brass and found an great load. It’s velocity was within 1 FPS of each other and was in the high .2s at 100 yards. Now that the brass is fire formed after I size it will it change any or not enough to matter?

 

[Kevinfarmer3456]

It could change..... will it.... only one way to find out. Most depends on how much difference there is between the new brass and your chamber deminsions.

Theoretically if the reamer used was a proper in-spec reamer and the brass was made within specs there should be very little to no difference. My guess is there will be a slight difference, whatever that's worth

 

[Bear]

It shouldn't change at all as long as they are shot in same rifle.

 

[Bowhunt]

It might change a little......just depends. Did you size that new brass before you loaded it the first time?

 

[hm1996]

IME new brass velocities run slightly lower than same brass after it has been fired. Usually doesn't make much difference.

Regards,
hm