sorting brass by case weight?

[LesD]

Ok reloading experts, here's a few questions for you.

How important is sorting brass by weight?

What is a reasonable tolerance in a batch?

I have fully prepped almost 550 pieces of Winchester 300WSM brass.  I know Winchester brass is not the greatest but it's the only reasonably priced show in town for WSM brass.  Norma brass is just way too expensive for me in such a large quantity.

The brass is for my F class rifle, where I need to extract sub .5MOA or better accuracy, certainly not BR accuracy so the Win brass is good enough.

I weighed every piece and sorted into two lots, 225.0 - 226.9 gr ( about 150 pieces) and 227.0 - 229.5 gr (about 400 pieces).  I culled out the few that came in under 225 and over 229.5 Yes I know the lots have different weight spreads.  I could not bring myself to throw out the the couple of dozen cases that weighed between 229.1 and 229.5and they are not useful to me as such a small lot so I tossed them in the next closest batch

Do I need to sort further?  Can I combine the two lots into one?
Is the weight difference going to make any measurable difference?

[John VM]

Take a couple of the really light ones and a couple of the heaviest ones and mix them up. Load and shoot them in a group and then shoot some that you have carefully weighed into a group. I have personally not been able to see a difference of 2 grains in a ppc sized case. If you can see what 4 grains difference in mag cases will do I would be surprised. Half this game is if you believe it makes a difference than it does make a difference. Case wall variation has more of a bearing on accuracy and the quality of the brass to withstand pressure and reloading is usually bigger issues. Lapua  usually has the advantage here but it never hurts to check.
 Did you weigh the cases after you sized and trimmed them?

[LesD]

Yes, cases were weighed as the final step after trimming, reaming pockets and flash holes, turning necks, cleaning etc.

I wish Lapua made WSM brass but sadly they do not.