Reloading - Trimming Cases To Length

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  • Reloading - Trimming Cases To Length

    A few articles coming on the general topic of reloading but a few individual sections for discussion like this one on Trimming Cases to Length.

    So, the basics for those that don't know a Cartridge Case has a SAAMI specified maximum case length that is safe to fit and fire in a firearm. If the case is too long then the case neck will be forced into the "Free Bore" of the Rifle Barrel and most likely be squeezed around the actual bullet in the case. If this is fired it can create an extremely high pressure build up in the chamber and possibly damage to the firearm. So, every Factory Calibre has a specified SAAMI Case Maximum Length but not all Calibres are of Factory Standards and commonly called "Wildcat Calibres". These Custom Chambers will be cut by a Gunsmith using a Reamer and that particular Reamer has a Print of Specifications with it and one is the Case Maximum Length suggested.

    All of these maximum measurements are just that, maximum and should never be allowed to grow past that dimension. The suggested Length to Trim the cases to is called "Trim To Length" and is quoted in most all Reloading Manuals but is normally 0.010" less than maximum.

    No, you do not need to trim cases every time they are reloaded but you should keep an eye on the case length and trim when it starts to approach maximum length. Some like to keep all their cases uniform and may trim to a specific length every reload or perhaps every two or three reloads. For precision shooting the case neck length has a factor involved with the amount of neck tension is applied to a bullet and if they are uneven then so is the neck tension and possibly accuracy as well.

    For the basic reloader who wants to trim cases. Well, Lee Precision make a pretty basic but very usable range of Case Trimmers consisting of a Cutter & Lock Stud in one Kit and the Calibre Specific Case Length Gauge & Shell Holder. The downfall of these is that all are set to cut at minimum case trim length and are not adjustable unless one modifies the Gauge Length. The downfall is they are only available for most Factory Calibres but not all. For example there is not one made for the popular .204Ruger Cartridge Case (last time I looked) as the story was it would need the whole tooling line to be altered.

    There is a work around by modifying a 22/250 Case Trimmer Gauge and hence why one is pictured....never did bother making one. That story later in this Topic.

    Here are the Lee Precision Case Trimmer parts.......











    The latter photo's are of the .22 Hornet set which I used to use.

    There are a number of ways to drive these and some wear off very quickly. You can hold the Lock Stud and rotate the Cutter, you can put the Lock Stud in a Handle and rotate any one you like, you can use what Lee make called a Zip Trim (like pulling the starter cord on the lawnmower) or you can use a Cordless Drill.



    Okay, no .204Ruger Trimmer so way back in those times I had to look around at what was available so I could trim my .204Ruger Cases. There are a number of adjustable Case Trimmers that use different Pilots for specific calibres....next stumbling block is that few if any made one for the .204Ruger or .20 Calibre in general .... never had a .17 Remington so that might have been the same story... Wonder how the .17 Hornet is going to go. Maybe the pressure will be on for manufacturers to come to the party.....anyway, I don't care as I found something way better.

    Enter the L. E. Wilson Case Trimmer ..... and it not only trims cartridge cases. Bullet meplats too....

    The basic version....



    The fancier Stainless Steel Micrometer version .....



    They use a Case Holder to keep the case parallel to the cutter centre and can be reversed if you want to square the case head. Also can be used to trim Bullet Meplats ......



    Then comes Bullet Pointing but that's maybe in another Topic .....

    Hope someone gets something useful out of all this ........


  • #2
    Great post Mega,

    I recently bought a "World's Finest Trimmer";



    They cost about $100 delivered from USA. They operate much like a pencil sharpener attached to your cordless drill.

    I am a big fan of it so far. Internally it uses a standard end mill cutter, so can be replaced with off the shelf cutters sourced locally. Trim time is a bout 4 seconds each case. Only downside is it is designed for individual case sizes only. I mostly only shoot 308 so this doesn't bother me.

    I bought mine from the manufacturer here; Little Grow Gunworks

    Cheers.

    Comment


    • Guest's Avatar
      Guest commented
      Editing a comment
      great post! I use lee trimmers (I also have a lyman neck turner and case trimmer - but I permanently loaned it to a mate because I never used it) just on meplat trimming - how important is it for accuracy?

      I've noticed that bullets (even match grade ones) are all inconsistent in length... I've considered buying a meplat trimmer - the sinclairs catalogue lists them for around $70 - so they seem quite affordable

    • Guest's Avatar
      Guest commented
      Editing a comment
      WFT... WTF trimmer more like it! It indexes off the shoulder but doesn't factor in the OAL.
      LEE gear is as good as it gets before you step up to the Wilson IMO. Speed, repeatability, and low cost. What's not to like!
      The LEE trimmer in the zip trim also allows you to deburr and chamfer and even polish the cases all in one device. Well thought out me thinks.

  • #3
    "Sumo" I had looked at the "WFT" but as soon as I spotted the case specific bit and not for some of the calibres I use I discontinued any further interest. Even if they covered my calibres I would be looking at over $1-1,500 just for trimmers. They had want to be pretty flash. Okay if you do one calibre but I do at least 15 different one's for not only myself.

    "nuthead" all good things come to those that wait, don't jump the gun. The Meplat Trimming and Bullet Pointing Topic is coming. Only so much daylight to take photo's of equipment. But I'll give you a little insight, Meplat Trimming makes very little difference to accuracy, Bullet Pointing make a big difference to Long Distance Accuracy...... to be continued.....

    Comment


    • moofy07
      moofy07 commented
      Editing a comment
      Originally posted by Mega" post=4422
      "Sumo" I had looked at the "WFT" but as soon as I spotted the case specific bit and not for some of the calibres I use I discontinued any further interest. Even if they covered my calibres I would be looking at over $1-1,500 just for trimmers. They had want to be pretty flash. Okay if you do one calibre but I do at least 15 different one's for not only myself.

      "nuthead" all good things come to those that wait, don't jump the gun. The Meplat Trimming and Bullet Pointing Topic is coming. Only so much daylight to take photo's of equipment. But I'll give you a little insight, Meplat Trimming makes very little difference to accuracy, Bullet Pointing make a big difference to Long Distance Accuracy...... to be continued.....
      I use the Possum Hollow trimmer, it indexes off the shoulder like the WFT trimmer but much cheaper (only in price).
      You buy an adapter to fit your drill (about $15), then you can buy different cutters (about $35-$40) some of the calibers are case family i.e. 222,223 221 FB etc.
      It will also take various case chamfer tools, inside and outside.
      I get mine from Hinterland Shooters Supply.
      By the way I used to use Lee cutters but were not as accurate as it could be.

  • #4
    Thanks for posting that Mega - I use the Lee stuff as well but run mine in the Drill Press, I put the case holder in the Press and then use the cutter in the hand, makes for a quick automated trimmer with good results (for hunting anyway)

    Cheers mate
    Whacking Varmints is my passion!

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    • Guest's Avatar
      Guest commented
      Editing a comment
      use the lee trimmer as well, cordless drill, easy as

  • #5
    Originally posted by Mega" post=4383
    Enter the L. E. Wilson Case Trimmer .....


    They use a Case Holder to keep the case parallel to the cutter centre and can be reversed if you want to square the case head. Also can be used to trim Bullet Meplats ......
    Can also be used as a run-out guage with the addition of a Dial Indicator.

    I made my trimmer based on the Wilson Design.
    I only need to turn up a case holder/bushing for each cal I want. No need for a pilot because I make the bushings all the same dia, turned & bored in one operation so they are perfectly concentric to be used for run-outs.





    Mick.

    Comment


    • Vromme
      Vromme commented
      Editing a comment
      Great post Mega. It would be great to see more like this.

    • Guest's Avatar
      Guest commented
      Editing a comment
      Your a talented man mick!

  • #6
    Recently went with the wilson case trimmer. Very impressed, quick ans easy to use. No need for a pilot and the clamping system is excellent.

    Comment


    • #7
      Thanks Mega.

      I would like to make some stuff too, but the lathe and free time it is on the boat in WA, and not keen to go through all the crap just to take EMPTY cases away with me, seeing as WA treat cases as ammunition with storage etc etc.

      Looking forward to more posts Mega

      Hope to fire off my first batches (testing powder weights for load development) of 30-30 this time home

      Comment


      • #8
        Cheers for the thread.

        Great looking reloading press (envy envy envy)

        TB

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        • #9
          Thanks for posting Mega, very informative---now keen on the Wilson trimmer with the micrometer--- darn more $$$$!!!
          Faster Horses
          Younger Women
          Older Whiskey
          More Money

          SSAA N52

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          • #10
            But money well spent

            Comment


            • #11
              Nice post mate, we need more useful info like this.
              Love your country, love your family, love your sport.

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              • #12
                Mega is this a better trimmer than the RCBS trim pro-2 case trimmer?

                John

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                • Guest's Avatar
                  Guest commented
                  Editing a comment
                  Originally posted by flyer" post=11876
                  Mega is this a better trimmer than the RCBS trim pro-2 case trimmer?

                  John


                  Sorry John for the late reply, been out of Internet Access for awhile. Lack of funds to pay the bill.

                  Bit late now as I see you purchased the Wilson Trimmer so hope you enjoy that.

                  As I mentioned in the first place I'm very wary of any Trimmer that uses Pilots especially with small calibres as they were either not made or very difficult to obtain. Wildcat chamberings probably in the same boat but one needs to think what they may use not only at the present time but in the future. At one stage I was looking at a Lyman Trimmer but I found there was not a Pilot for .20 Calibre (.204 Ruger) that I wanted to use.

                  Now doing Meplat Trimming is a big plus for the Wilson so I'm glad I went that way and have a collection of the Bullet Holders to suit my Target Calibres.

              • #13
                ordered a Wilson trimmer from BRT shooters supplies today only got the one rifle to reload
                so it will be cheap in my case

                Comment


                • 2208mate
                  2208mate commented
                  Editing a comment
                  Lyman Universal Trimmer
                  Has calibre specific pilots..
                  Can get a carbide cutter.
                  Can get a power adapter instead of a handle type.
                  Cutter adjustment via really fine threads to get length just right.
                  Will last a lifetime

              • #14
                I will only be setting this one up for .22 hornet so I hope it goes alright

                Comment


                • #15
                  I use the Dillon RT1200 set up in a Dillon XL 650 with the case feeder to process brass for the AR15's so I can process a lot of brass in one hit.
                  Brought the primer pocket swagger that fits in place of the primer seater so that I can be sure that every case is done. Much quicker then the Dillon Super Swagger and you don't have to worry about the difference in thickness of the case base.

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