Should I trim cases for accuracy?

Discussion in 'The Ammo & Reloading Forum' started by elkhntr, Sep 22, 2003.

  1. elkhntr

    elkhntr New Member

    Sep 14, 2003
    I have several boxes of once fired brass. I checked them to ensure that they did not exceed the max case length and noticed that they vary in length up to .01". Should I trim the cases (even though they are below the max length) so that they are a uniform length to get the most accurate ammo?
  2. armedandsafe

    armedandsafe Guest

    When cases are within .005" of one another, you will not get any discernable increase in accuracy, unless you are shooting a sub-MOA gun. With variances in the .01 range, I'd trim them, just to get everything uniform for that batch, as they age. If you are crimping necks, that is another reason to trim as uniformly as you can.

    My experience shows that cutting the last .005" will increase repeatability by about a tenth MOA. That was on two rifles over about 1000 rounds fired each rifle using 100 cases each (50 trimmed, 50 untrimmed.) Didn't increase my scores at all. Shooting grapefruit at 1K yards, the fruits didn't care.

    Last edited by a moderator: Sep 24, 2003

  3. Cliff

    Cliff New Member

    Trim them all. For me, accuracy is what counts. Accuracy means accurate length of brass, exactly the same amount of powder, same bullet, not just brand but brand and whether it is a BT, BTFMJ, BTSP, BTHP, HP
  4. elkhntr

    elkhntr New Member

    Sep 14, 2003
    Thank you for the information!
  5. inplanotx

    inplanotx Active Member

    Jan 28, 2002
    Okay, let me say this. The only thing accomplished by starting out with exactly sized brass is that the crimps will be the same. If you want accuracy, then you need to look at load density. That is the amount of powder in the case in relation to the air pocket. The higher the load density the more uniform the shot. This is also true for bullet pull and neck concentricity. These are all greater factors to accuracy than case length.
    Last edited: Oct 1, 2003
  6. Cliff

    Cliff New Member

    This is true. It seems like eons ago, 25-30 yrs, I had the priviledge of having some reloading facts drumed into my, yet untouched brain cells dedicated to learning about reloading. One needs to find the powder that completely fills the cartridge up and actually touches the base of the bullet. Since this is an exercise that altitudes, temperature, humidity reaks Billy Heck with, one cannot ever get the same loaded cartridge one behind the other. Doggone it, Plano! We forgot about reloading the same brand of brass. My .243 did not really like Remingto-Peters brass. They were more difficult to extract and they were difficult in chambering also. This is bad when these show up in one of the break-down guns (NEF)
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