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Thread: Brass jacket trimming and the effects on point forming

  1. #1
    Boolit Man
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    Brass jacket trimming and the effects on point forming

    This is not meant to be another how do you trim your jacket thread but rather your observations on the effect of trimming has on a jacket when point forming.
    I build my jackets out of 22lr jackets as do many here on the forum. Although I have built 55gn and heavier projectiles, I got into it to build 40 gn FBRN projectiles and these were and still are my main fodder.
    These short stumpy projectiles required me to trim my jacket to .460" and as I did not have a pinch trim die I built a end mill set up in a drill press to trim the jackets square and to length.
    This works a treat and takes about 5 seconds, but I thought it slow and laborious but made a very fine jacket.
    I never had a folded tip with the 1E PF die or with the 6cal PF die that I now have with any jacket that was trimmed with the end mill. I did build 52 and heavier projectiles with success but tended to get a few folded tips with jackets that had not been trimmed but just derimmed. I then ventured into 17 cal and drew my jackets down and trimmed with the same set up again no folded tips and very accurate projectiles.
    I then invested in a .224, ET-2 pinch trim die from D Corbin as I thought it would speed up the process. This has proved not the case as you still have to knock some of the waste jacket off by whatever means suits you and the cut edge is nowhere as neat as a machined one. I also believe that the pinch trimmed edges from this die have a lots flaws in them. As with every thing, I made a trial run of 100, 40gn FBOT, 1E projectiles and over 80 % of them had folded tips and had to be discarded as seconds. I have made thousands of these and so I am happy with my process, so I was very disappointed with this result. I am a firm believer that folded tips have a lot to do with flaws in the case mouth and not necessarily from poor annealing practices or poor dies.
    I have also picked up a 17 cal draw / trim die. This works differently and trims the waste off beautifully and have not had any folded tips but I have not tested them over 4K yet, while the machined trimmed jackets have been tested, without failure.

    Do any other swagers who trim jackets to suit their needs have this problem or have any thoughts on a better way.
    I know BT Sniper is thinking of building a trimmer of some description and hopefully may chime in with his thoughts.
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    Billsshed
    The bloke out in the field is always right until proven otherwise.

  2. #2
    Boolit Master
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    I too started jacket trimming with a 35 cal pinch trim die and was never happy with the mouth of the jacket so I made a set up using a 1/2 in carbide end mill on the milling machine. I have been trimming some long 25 cal jacket derived from 1.15 long Sierra 30 cal jacket. After drawing, these 25 cal jackets are very long and require removing almost 1/2 in to make a 100gr bullet. I use a 5C collet with an adjustable collet stop inside it. The collet is placed in a vertical collet closer on the table of the milling machine. With the spindle down against it's stop, the adjustable stop in the 5C collet is set to the desired jacket length. With so much material to be removed, the end mill must be lowered slowely. I do it in many small steps to avoid heating the jacket very much. The collet closer must be quite tightly closed to avoid spinning the jacket in the collet. Raise the spindle, loosen the collet a quarter turn, remove the trimmed jacket and you are done. I use a few light twists with a regular deburring tool(just like cartridge cases) to clean out the mouth. A blast of compressed air removes shavings from the jacket. This method gives you a nice clean edge on the jacket mouth.

    When using cartridge cases for jackets you just use your regular case trimmer.

    Bob
    Si hostes visibilis, etiam tu

  3. #3
    Boolit Man
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    OWE ! That's not really what I wanted to hear. I'm not a machinest, but I have been looking forward to getting a trim die from Dave for a 22 Hornet I have that has a short magazine and wont run the longer bullets. I'll be keeping my eye on this one.

    P.S. That's a really good looking OT bullet you got there !

  4. #4
    Vendor Sponsor uncle dino's Avatar
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    Is there any way you can trim jacket prior to annealing? Pinch trim works much better with jacket a little harder.. D

  5. #5
    Boolit Man
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    I have tried annealing the case prior to trimming and the case just crumpled. As I have a temp controlled kiln I tried less heat for less time to make them harder all the way through dead soft. All crumpled. On his site for the ET-2 Dave Corbin shows his external punch having a long taper. The one he sent me is very blunt.

    Midnight,
    Sounds very similar to my set up but I run my collet system in a drill press with a 4 flute tool steel end mill. Lower cutting forces. I am going to fit a small pneumatic cylinder to the collet locking system and also the ejection system. After I have trimmed, I anneal and then throw them into the tumbler. They come out clean and the swarf is removed at the same time.

    Bill
    The bloke out in the field is always right until proven otherwise.

  6. #6
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    I have the pinch trim dies with the long taper and the "blunt taper". I do not see any difference in performance.
    New England Custom Bullets Inc.
    13 Maywood Rd
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    845-391-7679

    Email: pete@newenglandcustombullets.com

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  7. #7
    Boolit Man Alex_4x4's Avatar
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    Last edited by Alex_4x4; 01-08-2018 at 09:22 AM.
    Viam supervadet vadens.

  8. #8
    Boolit Man Alex_4x4's Avatar
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    Well form meplat this tool: http://www.bullettipping.com/product...ippingdie.html

    TP-B11
    Viam supervadet vadens.

  9. #9
    Boolit Man
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    BM57,
    Do you still get folded tips making those 224 projectiles? I have no dramas that the ET-2does work. Do you anneal the cases or "as fired"? I Thought it would be a bit more efficient. The brass jacket sample that came with it was slightly squashed from when they removed the waste with a pair of pliers or other tool. Compared to a machined finish it seems rather rough.
    Alex, any detail on those projectiles and the finish you get with the pinch trim?

    Bill
    The bloke out in the field is always right until proven otherwise.

  10. #10
    Boolit Man Alex_4x4's Avatar
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    There are no special tricks for forming the tip of the bullet. All brass fringe is removed with this tool: http://www.bullettipping.com/product...ippingdie.html
    Viam supervadet vadens.

  11. #11
    Boolit Man
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    Hi Alex4x4,
    Nice tooling for those that want it but I have no issues with tip forming if the jacket has a machined mouth. I am finding I get many folded tip if I have used the Pinch trim style. Do you get some folded tip after you have trimmed the jacket. I see you also use the ET-2 style trimmer.

    Bill
    The bloke out in the field is always right until proven otherwise.

  12. #12
    Boolit Master
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    I've used the ET-2 style trimmer and haven't had any folding issues. For me proper annealing is the key.

  13. #13
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    My experience is the same as MIBULLETS. Proper anneal, no folded tips.
    New England Custom Bullets Inc.
    13 Maywood Rd
    Newburgh, NY 12550
    845-391-7679

    Email: pete@newenglandcustombullets.com

    PayPal:pete@newenglandcustombullets.com

    FFL

    http://castboolits.gunloads.com/show...ullet+maker+57

  14. #14
    Vendor Sponsor uncle dino's Avatar
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    When making the open tipped bullet. If the lead is too far back from the tip, the jacket will be prone to folding or creasing.. Because the jacket is unsupported, it will magnify any imperfections and cause it to fold. I'd try to shorten the jacket some, or make a little heavier bullet. D

  15. #15
    Boolit Man Alex_4x4's Avatar
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    Products made of cartridge cases .22lr, in my case, this is a very budget option. I'm using .22lr. from a Russian manufacturer. Requirements from my customers on the quality of these products allow the presence of folds. Products made of .22lr are used by my customers for entertaining shooting and hunting. The price of these products is about $10 for one hundred pieces.

    For this price and vinegar is sweet.



    Those who want better products order from me bullets in the material of the envelope J4. But the price is different (more).

    In general, I do about 35,000 to 40,000 products per year. Demand is there and work. If possible, expand the range of their products.

    If interested, then you can look at my "business" here: https://forum.guns.ru/forummessage/153/940687-220.html
    Viam supervadet vadens.

  16. #16
    Boolit Master Mauser 98K's Avatar
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    that is why i anneal and seat the core b4 i trim. this takes a custom trimmer to do but is the way i do my bullets.. i anneal, seat the core, then i trim, and this keeps the jacket from crushing. i will also lightly skin the end of the jacket after trimming with my electric case trimmer so that the ends are completely square with the bullet, there are no burrs, and they all come out at exactly the same length with a nice neat end on the finished bullet. makes them look a lot more like commercial bullets this way..

    but i also found out that if the trim punch is at too blunt an angle that it will put too much stresses on the jacket and try to accordion/squish it. I'm using a 60* taper on my trimmer.

  17. #17
    Boolit Man
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    Thanks for all the input.
    It sounds like I am not the one who prefers a better cut jacket than a pinch trimmer produces. The machined jackets are square and perfect length. Once point formed the length variation is minimal and no uneven meplat.
    I will keep playing with the pinch trim die but it is no quicker than what I have made. If anybody has better ideas, I am sure all here would like to hear it.

    Bill
    The bloke out in the field is always right until proven otherwise.

  18. #18
    Boolit Master BlackoutBuilder's Avatar
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    Well, I love these. They use an end mill and a bearing. They are adjustable too. https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
    NFA = Not Freaking American

    It would be less disrespectful to burn the flag than to put a thin blue line through the middle of it.

  19. #19
    Boolit Man
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    I like the idea....but my little jackets are only .460" long. They would get lost in that beastie!
    Do they work with straight wall cases?

    Bill
    The bloke out in the field is always right until proven otherwise.

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