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weight of brass cases

dchristian
I have been reloading rifle and pistol ammo for about a year or so. I have tried to be fairly careful about powder weight, case sizing and trimming, cleaning the brass, but I find that there is quite a weight variance between the cases from same manufacturer and batch. Recently, I found my 270 brass, which had been cleaned, sized, primed, and trimmed varied in weight from 185 grs. to 195 grs. Is that normal? How much variance is accceptible before it starts to affect accuracy?
Thanks in advance.
dchristian
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  • heavyiron
    Hi,

    Yes brass will deviate by that much and a little more but don't panic. Due to manufacturing tolerances there will be slight differences in dimensions and weight. The 10 grain difference you mention is only 0.02 ounces or .0015 pounds. This is not a great amount.

    Match ammunition is usually held to tighter tolerance than sporting ammunition.

    The other factor worth mentioning is that if the rifle is used for hunting this difference probably doesn't make any difference. We all want our rifles to be as accurate as possible but most hunting rifles are really set up to put a projectile in a 6 or 10 inch kill zone at 100, 200, or whatever yards. Any differnce 10 grains of case weight will make under these circumstances in the field, won't even show up on the radar screen.

    If the rifle is used for precision target shooting at 1000 yards or bench rest shooting, then that is a completely diffent matter, and the 10 grains may make the difference between a .2-inch group and a .3-inch group which would be important. The rifle must also be able to deliver this type of accuracy. Many match shooters will weigh out their brass and sort them by weight. For example, they may weigh all the brass in a batch and retain all the cases that are within 5 grains of each other. This type of consistency is essential for the utmost in accuracy for major match competition but not for hunting plinking.

    Hope this helps.

    Regards,

    Heavyiron



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    "If I don't see you nomore on this world, I'll meet you on the next one, and don't be late!" - Jimi Hendrix
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  • dchristian
    Thanks for the input.
    dchristian
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  • Tailgunner1954
    How much the variation (BTW I've seen 50gr variance within the same headstamp, different lots, of 30-06 brass) will effect your accuracy, will depend on how accurate your rifle/load is. IE if you have a 1.5MOA rifle, the difference won't be measurable, on the other hand if your shooting a .5MOA rig, it might matching the internal volume (which is the idea behind weight matching brass) drop you into the "4's".

    Whittemore
    Some guys like a mag full of lead, I still prefer one round to the head.
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