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Thread: Tapered Crimp

  1. #1
    Boolit Buddy
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    Tapered Crimp

    I have been collet crimping my 45-70 greasers loaded with smokeless. I’ve read that a light taper crimp is best for PPBs. Does this mean that I need a new special die to crimp with? Is there one make that is better than others?

  2. #2
    Boolit Master

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    i'm not sure what yer goal is, but with black powder PPBs i fill the fire formed (or pseudo fire formed) case to the rim with compacted black powder (compaction happens when the powder is drop tubed or the case is vibrated), insert a wad, compress to .100" of the rim, place the PPB into the case mouth and run that up into a pre-adjusted .45-70 taper crimp die that adds a very Very slight amount of case mouth squeeze (not a crimp) so that the PPB won't fall out and yet will twist around and can be pulled out with fingers.

  3. #3
    Boolit Grand Master

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    Im similar to rfd I drop charge add wad and compress. Hand seat the bullet onto the wads. I then size around the bullet with a Meacham bushing die and the correct size bushing. this holds the bullet lightly in place. The taper crimp should work about the same, but be carefull as to heavy crimps on PP bullets can damage the Paper wrap.

  4. #4
    Boolit Master

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    basically, with PPBs, never do a real crimp as that will cut into the patching, as CG posted above. not having a crimped in bullet is a good thing, as the best crimp is no crimp, which means no concern over neck tension variations to affect accuracy. another plus for PPB cartridges.

  5. #5
    Boolit Master Good Cheer's Avatar
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    Quote Originally Posted by GregLaROCHE View Post
    I have been collet crimping my 45-70 greasers loaded with smokeless. I’ve read that a light taper crimp is best for PPBs. Does this mean that I need a new special die to crimp with? Is there one make that is better than others?
    Big bro' is using straight lead swaged and paper patched in his 45-70 Marlin lever gun with smokeless. He has had to buy a taper crimp die to make it come together with not single feeding. He's shooting quarter sized groups at a hundred with all the patch inside the brass. But that's the way lever guns are, special provisions required to protect the patch but not strip it when it comes out the chute and jumps to the rifling. He also had to reduce his final diameter to groove, to get the patch into the rifling undamaged. After decades of shooting paper patches and working his way through various problems encountered he should write a book to supplement and correct the works of Paul Matthews.

  6. #6
    Boolit Master

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    It might be better to revive the old term “case mouth reduction” to cartridge cases formed to hold paper patched boolits after seating, and stop using the word “crimp.”

    “Crimp” has always implied rolling over the mouth of the case into (hopefully) a groove in the bullet (jacketed or cast) to form a mechanical interlock between the two. The designation “taper crimp” has distorted this concept, since it was not intended to roll the mouth of the case over (which would increase headspace in rimless straight cartridges used in autoloaders), but to increase the friction of the case wall against the bullet after it was seated so it would not move during the loading cycle. Since it was a replacement for the ordinary crimping operation in reloading, it picked up the nomenclature even though it is really nothing of the sort.

    A roll (actual) crimp may or may not impair accuracy under normal circumstances, depending on bullet design, powder pressure balance point and the gun used, but, of course it is always fatal with a paper patched boolit because of the fragility of the paper. It is natural that a handloader, wishing to expand his skills into this area, would take the term as he had always understood it, and wind up wondering why his reloads do not perform. Dropping the word “crimp” in this case would save a lot of repeated explanations to disappointed shooters.

  7. #7
    Boolit Grand Master

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    One problem with the current dies and bore riding PP bullets is they are desighed to size the case down for the .458-.459 dia bullets normally used. They do size down a couple thousandths smaller and neck expander sets to size to work with all the neck wall thicknesses, but not enough for the light fit wanted with bore riding PP bullets that measure in the .449-.451 range. With these a different size is needed to make the correct fit. An existing die cant be made smaller easily this becomes a little trickier. If a 45 colt or 45 acp die can be set high enough to size just the neck with the full stroke it can be very close to whats needed and then the correct expander to bring to size for PP bore riding bullets. This is a make do fix that may or may not be completely effective.

    The bushing dies allow for the correct size with a simple change of the bushing, no expander is needed since you only size down what you need for the batch of brass. You can get just what you want need in this way. The initial die is a little more expensive and the bushings can add cost. My Meacham die and bushings will neck size 45-70, 45-90 ( with the same 2 sets of bushings) 40-65 ( new bushings were needed here). Both for Bore riding paper patched and grease groove bullets as said above with a simple bushing change.

    a 45-70 die can be converted to bushing with a lathe carefull measuring, set up and some work. I have done it on other dies before. You need to set up the die and indicate it in to true. drill out decapping threads to depth required and bore to size for bushing with a flat base. Then tap the top of the hole. ( I believe I used 5/8 18 threads) Turn up a cap to thread in and lock bushing in place. turn bushings and bore to size. the cap can be bored thru .470-.475 hole if you decap seperatly and this allows for sizing after bullet is hand seated. or tapped for a decapping rod if that's desired. Polish and break all the sharp edges from remachining the die.

  8. #8
    Boolit Master

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    right on, it's a "reduction" or "squeeze" and not at all a "crimp" of any kind. this is for single feed guns, as expected. magazine guns are a whole 'nother story.

  9. #9
    Boolit Buddy
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    The Meacham die and bushings seems to be the cat’s meow, however the total setup is a bit pricey for just starting out. Also I am not 100% sure of what size I would need, so would have to buy several bushings to start. Isn’t there a simple taper die for .45-70 I could start out with?

  10. #10
    Boolit Master

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    greg, you don't need any specialized dies to make good .45-70 PPB or greaser cartridges. if yer doing PPB cartridges, you might only need a .45-70 taper die at best, and add a compression plug in a lyman "M" die body and maybe a .460 straight expander in a lyman "M" die body. i use a lyman taper die, $26 @ midway.

  11. #11
    Boolit Grand Master

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    Greg If you have a friend who is a machinist, or a vocational school near you its not hard to convert a standard die to use bushings. For the bore riding paper patched this works fine. But you cant go bigger than the original die is for grease grooves. unless you ream the die taper out a few thousnadths. ( .002-.005 )

    I like my meacham die but it gets used for 3 calibers and 5 rifles.

    Modifying the 45-70 die isn't super hard its more paying attention to set up and measurements. Remember your 1/8" shorter on the case do to the shell holder. measure up from the bottom of the die to where you want sizing to stop ( bottom egde of bushing) and then from this point to top of die. ( your working from the top of the die this gives a solid dimension that can be measured easier). drill out the die to 5/8" to depth, bore to size and flatten shoulder. A slight under cut here can be a plus. Tap to 1/2" from bottom (Bushing thickness ) and break sharp edges if you want ream out .005 on die thru to allow more range. Turn up the cap put a 1/2" hole thru it and a bushing dia step on the end .50-.100 long to clamp bushing in tight. I used fine threads here. When done you have a die that will still size the base and most of the body, yet is bushing adjustable for neck size tension. Bushings can be made as needed from pre hard 4140.

    To get an idea of bushing size measure the neck wall thickness of your brass and the bullet dia.
    Neck wall thickness X 2 + bullet dia = bushing size for no tension fit.

  12. #12
    Boolit Master

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    i also use a lyman .45-70 SIZING die to apply the final PPB/case neck "squeeze".

  13. #13
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    I've used a 30'06 FL sizing die to just kiss the case mouth enough to hold the boolit in place on a 450 No.1 Express.
    Works fine and I would expect it to work on a 45/70.

  14. #14
    Boolit Master
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    Quote Originally Posted by Huvius View Post
    I've used a 30'06 FL sizing die to just kiss the case mouth enough to hold the boolit in place on a 450 No.1 Express.
    Works fine and I would expect it to work on a 45/70.

    Innovative! I like it.

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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check