Trimming 300 Savage cases

Discussion in 'The Ammo & Reloading Forum' started by nevadal, Jun 20, 2012.

  1. nevadal

    nevadal Member

    Apr 13, 2012
    I have cleaned, deprimed, & sized my brass, now for the trimming.

    The book says that max COL is 1.871. Trim length is 1.861.

    As I am still pretty new to this, while getting my RCBS trim pro-2 set up,
    I used several casings to get the right trim length....while doing that, I ended
    up with lengths of 1.854 to 1.858, do these go into the discard bin, or can
    they be used.
    So far I haven't found anywhere that tells + or - book specs.

    I will be using Hornady # 3045, 165 GR BTSP bullets, & IMF 4064 propellant.

    Appreciate any help....thanks.
  2. Bindernut

    Bindernut Well-Known Member

    Oct 24, 2007
    ND, USA
    Typically, the "trim-to" length is 0.010" shorter than the max case length as listed in the SAAMI specs. That is the +/- range you'll want to try to stick within when trimming. Once a case reaches or exceeds the max length, then it's time to trim it to the trim-to length.

    Are you using the cannelure (crimp groove) on that bullet?
    If not, then I usually wouldn't worry about that missing 7 thousandths.

    If you're planning on crimping them in the groove, then I wouldn't use those cases for those loads at all. Save em for loads with non-cannelured bullets or just don't crimp the bullets after seating them. With inconsistent case length and crimping to the groove you will have inconsistent overall length which can monkey with your accuracy.

    But...That extra 0.003-0.007" isn't enough to cause problems with most cases but in the case of the .300Savage you don't have very much neck length to begin with. You might notice those cases aren't quite as accurate because there isn't as much neck tension as proper trim-to length.

  3. Alpo

    Alpo Well-Known Member

    Feb 3, 2007
    NW Florida
    But after you have loaded and shot them four or five times, they should have stretched out to long enough.
  4. Hammerslagger

    Hammerslagger New Member

    Jul 30, 2009
    I'll ditto post #2; and add that for serious tight grouping bench-rest type accuracy you want to keep your cases uniformly trimmed to just under max length. Just check and adjust their length after each resizing.

    I have mentioned the following here before, but will do so again because it is not well know by many reloaders. In years past, some reloading manuals made little mention of it; and I do not have a recently published manual handy.

    The following applies mainly to bottleneck, 40K psi and greater, rifle cartridge cases that are reloaded more than a usual number of cycles, like 10 or more; or have been formed from brass of another caliber.

    The pressure of firing causes the brass to flow forward. Thus, cartridge the case grows longer; but it also grows thinner near the case head (primer end) and thicker in the neck area. Therefore, it is a very good and safe practice to measure and make sure that the outside neck diameter or your reloaded cartridges does not exceed the max blueprint dimension. As little as 0.002" over max dimension can cause serious pressure problems in a rifle with a very tight (but still within blueprint) chamber.

    Be safe not sorry.

    Usually cases that are getting very close to max dimension in the neck are best retired
    Last edited: Jun 20, 2012
  5. nevadal

    nevadal Member

    Apr 13, 2012
    Thanks guys, as always I appreciate y'all sharing your knowledge
  6. LDBennett

    LDBennett Well-Known Member

    Dec 20, 2003
    Hesperia, CA

    While it is best to trim the cases to spec, the cases that got trimmed too short are not really a problem for your 300 Savage. At no more than 0.007 inches too short, it will not effect the crimp (if this is for the Model 99 lever gun you MUST crimp the cases as the cartridge handling during feeding and while riding in the gun during recoil could cause the bullet to change seating depth). They will stretch eventually to the correct spec.

    Think about it: "0.007 inches". Set up your calibers to that dimension to see how much that really is. The gun and the case will not be able to detect the difference, especially if you are using the ammo in a lever gun and are not bench rest shooting in competition. I doubt most target shooters would find any group size difference with that small amount of variation in the case length especially with crimped ammo.

  7. Sherrer1*

    Sherrer1* Member

    May 24, 2012
    Selma Alabama
    I use a lock and stud cutter from Its great how it works is after you deprime and resize it. But you also have to buy the pin for whatever caliber for it that chucks into your cordless drill. There is a studd that goes inside your brass and through your flash hole but quits cutting when you have the correct length.
  8. LDBennett

    LDBennett Well-Known Member

    Dec 20, 2003
    Hesperia, CA
    I use a RCBS Trim Pro Power Case Trimmer. It is easy to use, motorized, automatic, and trims the cases all to within a thousandth or two of each other. I trim to the manual listed "trim-to" length when any of the lot of cases exceeds the max case length. I do it AFTER de-priming and sizing as the sizing completely changes the case OAL. The bottom line is that after sizing and trimming the case must be no more than the max case length or the case will jam into the bore of the barrel and make horrendously high pressures. See the Hornady reloading Manual for details.

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