Originally Posted by tbrice23
I have been forming 7mag brass with h1000 all week. Velocity jumped 100fps from gm210m to cci250 verified by two chronos back to back then reversed.
I would expect new brass to expend a lot of the powders energy to expand. Meaning new brass velocity would be slower. However new win. brass 72gr h1000 cci250 168vldh was 3020/3024fps 24 in bbl. Thats pretty fast for that load.
Do you always see lower speed same load on once fired brass?
My experience with fired vs new brass and the effects on velocity is dependent on the rifle's chamber. I measure the case capacity between the two. If the capacity changes, the velocity can as well, all other as parameters of the load reminding constant. Generally, larger case capacity results in lower velocity under this circumstance. I have also found Winchester brass to be thinner in wall thickness which can pronounce the chamber/case capacity effects.