Federal vs Winchester Brass Performance

[WV338]

I'm shooting a 300 WSM with 165 gr Nosler AB over 60 grs of RL-15 and CCI 250 primers. I loaded up 10 rounds in Federal and Winchester brass. I was very surprised at the difference between the two. The Federal shot 40 fps faster (3070) than the Winchester brass and it shot 2" higher. Both are sub MOA. Ballisticly the 40 fps difference shouldn't make it shoot 2" higher.
Has anyone had any similar experiences?

 

[handloader1]

Federal Brass seems to hold more powder. I have never weighed usefull case capacity with water, but I bet someone on this forum has. I really like Federal Brass. Good luck.

 

[MSLRHunter]

I haven't used much federal brass, but I have always heard that it sometimes holds a little more powder and it tends to run a little soft. I mostly use Winchester in my 300 win mag and once it is fully prepped it is good brass.

 

[WV338]

I posted the same question on another site and I think the gentleman may be right. He said it has to do with neck tension. One thing I left out of the post was that the Federal was new brass while the Winchester was twice shot brass. I think that is the difference.
Thank you all for your input.

 

[green 788]

FC cases are on average thicker, with less volume internally... so they have more pressure build up with the same powder charge. And they're on the soft side, and won't last as long as Win and Rem... neck tension will tend to vary too much for good consistency after a couple of firings.

Someone out there may have some FC cases that represent the exception to the rule... but it's just that, the exception.

Dan