Case trimming

Discussion in 'Reloading' started by teampete, May 22, 2011.

  1. teampete

    teampete Well-Known Member

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    Hey all, I am trying to learn as much about reloading as possible and also get started on this venture. I am a little confused on wither I should trim each case every time I reload. Buddy of mine said he trims the case everytime because after shooting it expands and gets longer. But he said he knows some guys that trim just once and trim a ways back. He said they trim enough that when the case expands it is still in acceptable range. MY question is that having different case lenghts every time effect accuracy? Also how do I figure what is the optimum case length for my rifle? I am trying to decide if i have to buy a case trimmer right now. Cash is low and it has taken me a lot of money to get started in reloading so I am trying to figure what else i need.

    Thanks all I really appreciate it and hope my question makes sense.
     
  2. SBruce

    SBruce Well-Known Member

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    You will eventually need to trim your cases, but hopefully you can get at least a couple/few reloads before they get to that "maximum" length.

    I've never been too concerned with "optimum" length, perhaps others do.?

    FWIW, I have always waited until they get close to that maximum length and then trim back about .010" to .012" I'll trim the whole cartridge box at that time. So I'll generally have at least 50, or 100 cases trimmed to the same length at that point.

    Neck sizing has allowed me to maximize the number of reloads between trimming sessions. Seems that most times I FL size, the cases lengthen by a few thousanths each time.

    There are two ways that I know of on "how to determine max case length". One, is just go off the reloading manuals' dimension. Most will list a max length or a trim to length. The other way is to buy a cartridge length guage or have one made by a machinest. The guage will tell you the real length of the neck in your chamber. When the cases get close to that length, trim back at least .005 to maybe .015" kinda your choice on how far back you go, but if you only go .005, you'll be trimming more often.
     

  3. Edd

    Edd Well-Known Member

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    You don't have to trim every time but I normally do. I use a Lee trimmer for some of my stuff. You can buy one of those for under $20.
     
  4. teampete

    teampete Well-Known Member

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    Thanks for the info guys. Are you refering to the lee zip trim?? I look at it and it seems really nice. It also allows you to debur the case too. Do you reccomend the check with the zip trim or just the shell holder?
     
  5. Edd

    Edd Well-Known Member

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    I don't have a Zip Trim. I either turn them manually or with a drill.
     
  6. newmexkid

    newmexkid Well-Known Member

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    Right now I'm only reloading for 2 rifles so I can keep pretty good records without much fuss. I keep all my cases in numbered plastic boxes and generally don't worry about trimming until that particular box is coming up on it's 5th reload. Then again I don't shoot max. loads so I think that has some bearing on how many reloads you can get in between each trimming, (I think).
     
  7. SBruce

    SBruce Well-Known Member

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    I think that probably does have an effect too.

    Also, the particular cartridge being shot/loaded has an effect. For example, my old 220 Swift required trimming about every 3rd firing with only 1 FL sizeing in there somewhere and shooting fairly mild loads.
    It's replacement (a 6 Long Dasher) has 8 fireings on a case, 3 FL sizeings with pretty warm loads and no measurable lengthening of the case so far.

    All other rifles I've owned have been somewhere in between these two.