Roll crimp or taper crimp for 357 magnum ammo/revolver cartridges
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cjwils
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As long as you have a good, strong crimp, I don't think it matters whether rolled or tapered. But there is one exception. If you use the cartridges in a lever action rifle, you need a rolled crimp. The square leading edge on a case with a tapered crimp can hang up on some of the edges in the action.
It's been my experience that the manufacturer of your loading dies has already decided this for you, and your choice now becomes "do I want a roll crimp or NO crimp?"
If you have 9mm dies, your question is "do I want a taper crimp or NO crimp?"
When you are making revolver ammo, you are almost always going to apply a roll crimp to some degree.
If you have 9mm dies, your question is "do I want a taper crimp or NO crimp?"
When you are making revolver ammo, you are almost always going to apply a roll crimp to some degree.
cjwils
Member
I have not experienced the situation described by Sevens. My reloading die sets for revolver calibers all came with a tapered crimp. If I want rolled crimps I have to buy an additional roll crimp die.
I have always roll crimped revolver cartridges, and taper crimped semi auto cartridges, even if the semi auto cartridges are used in a revolver.
The rule of thumb used to be, if the bullet has a crimping groove, roll crimp. If it doesn't, taper crimp. This doesn't really hold true any more as some plated bullets I use in .357 and .44 revolvers don't have crimping grooves but I still roll crimp.
The rule of thumb used to be, if the bullet has a crimping groove, roll crimp. If it doesn't, taper crimp. This doesn't really hold true any more as some plated bullets I use in .357 and .44 revolvers don't have crimping grooves but I still roll crimp.
Another (related) issue I see often is that folks believe a taper crimp is supposed to give them some manner of strength or enhanced strength in holding a bullet in place. That's not what a taper crimp does. Handloading discussions might be a little more clear if the term "taper crimp" were stricken from the record and the act were given another name that doesn't use the word "crimp."
A taper crimp removes/repairs the previous step of flaring the case mouth and returns the brass to a shape that the handgun is expecting and enjoys.
A roll crimp adds to a cartridges ability to hold on to it's bullet under different forms of stress. That's a large part of it's purpose. That's not the purpose of a taper crimp. The taper crimp is to prepare the assembled cartridge for proper, expected feeding.
This is a matter of much frustration, discussion and argument over many years.
A taper crimp removes/repairs the previous step of flaring the case mouth and returns the brass to a shape that the handgun is expecting and enjoys.
A roll crimp adds to a cartridges ability to hold on to it's bullet under different forms of stress. That's a large part of it's purpose. That's not the purpose of a taper crimp. The taper crimp is to prepare the assembled cartridge for proper, expected feeding.
This is a matter of much frustration, discussion and argument over many years.
rockquarry
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I've taper crimped and roll crimped .357 ammo. Taper crimp holds bullet as well as roll crimp, but I use only cast bullets. May be a different story with jacketed bullets.
cjwils
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A taper crimp can be strong enough to firmly hold the bullet. That is the norm for cartridges used in semi auto pistols.
I go with a roll crimp on revolver cartridges. I guess I am just a traditionalist.
Except that it isn't. The taper crimp isn't doing that job and doesn't deserve the credit you're giving it.
Using decent brass of proper construction, sizing your brass, flaring no more than necessary and using bullets that play well with your brass (dimensionally speaking) is what gives your semiauto handloads their ability to hold that bullet.
It isn't the taper crimp.
bigggbbruce
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RCBS ships all there revolver calibers with a roll crimp die.. they offer 38/357 with taper crimp.. but that's not their norm..
In the olden days when I forst started hand loading, I roll crimped revolver, bottleneck or rifle cartridges and taper crimped straight wall semi-auto cartridges
These days I much prefer a collet crimp on all of my heavy 357 Magnum loadings.
These days I much prefer a collet crimp on all of my heavy 357 Magnum loadings.
A taper crimp might work but I wouldn't choose a taper crimp over a roll crimp.
Like Sevens has said, a taper crimp is good at removing the belling from an expander die. You don't want a roll crimp on auto-loader rounds.
If you're using revolver bullets without a crimp groove or cannelure a taper crimp might work, but you'd probably be better off getting more appropriate bullets.
Like Sevens has said, a taper crimp is good at removing the belling from an expander die. You don't want a roll crimp on auto-loader rounds.
If you're using revolver bullets without a crimp groove or cannelure a taper crimp might work, but you'd probably be better off getting more appropriate bullets.
Pisgah
Member
I have never seen a set of dies intended for a revolver round like .357 that didn't have a roll-crimp die. Never saw a set with taper crimp die except for semiauto cartridges. And that is how it should be for revolvers or lever action rifles -- roll crimp only.
gwpercle
Member
The correct answer is Both. Cast lead with a good crimp groove get a roll crimp . Smooth sided , like berry's plated or many cast 9mm bullets that have no crimp groove or cannelure get a taper crimp . I use 9mm Luger taper crimp die in 38/357 .
Jacketed bullets with a cannelure : if crimping into the cannelure a light roll crimp. If seating above or below the cannelure , which sometimes occurs , you can taper crimp.
In reloading there is never a yes/no , right/wrong or better/worse answer. You have two ways of doing something, you have to learn why there are two ways and select the better way for the bullet and case being loaded . Both taper and roll have their places, one isn't superior to the other.
Gary
Jacketed bullets with a cannelure : if crimping into the cannelure a light roll crimp. If seating above or below the cannelure , which sometimes occurs , you can taper crimp.
In reloading there is never a yes/no , right/wrong or better/worse answer. You have two ways of doing something, you have to learn why there are two ways and select the better way for the bullet and case being loaded . Both taper and roll have their places, one isn't superior to the other.
Gary
I roll crimp revolver cartridges, taper crimp semi-auto pistol cartridges. I tried taper crimping Ranier plated bullets for 357 Magnum, loaded to mid-range velocity. The bullets did pull forward during recoil, so I went back to cast or jacketed revolver bullets and a roll crimp.
rockquarry
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After reading the comments and so that the initiating poster knows for sure, it would be best to try both roll and taper crimping and maybe any variants of these methods using the appropriate dies.
Regardless of whatever crimp die is used, I've found it best to apply no more than minimal crimp, just enough to prevent bullet movement under recoil. Regrettably, there is no real definition for degree of crimp. Light, medium, and heavy mean different things to handloaders, but "minimal" is easier to define than anything else.
I've yet to find a need or advantage for a crimp any heavier than that required to prevent bullet movement under recoil. Too much crimp may affect accuracy adversely due to bullet distortion. Reportedly, too little crimp will hamper proper ignition. While there are always exceptions, I've never seen a crimp negatively affect ignition, so I'll presume my minimal crimping has worked well.
Regardless of whatever crimp die is used, I've found it best to apply no more than minimal crimp, just enough to prevent bullet movement under recoil. Regrettably, there is no real definition for degree of crimp. Light, medium, and heavy mean different things to handloaders, but "minimal" is easier to define than anything else.
I've yet to find a need or advantage for a crimp any heavier than that required to prevent bullet movement under recoil. Too much crimp may affect accuracy adversely due to bullet distortion. Reportedly, too little crimp will hamper proper ignition. While there are always exceptions, I've never seen a crimp negatively affect ignition, so I'll presume my minimal crimping has worked well.
^That's well put, especially where you say that "minimal" is easier to define.
I have personally found however, when you get in to the big stuff, you've got to get downright hardcore with the crimp. .460 S&W Magnum at 60,000 PSI. Yes, for sure the other rounds wish to lurch under recoil, but I've also had examples (more than I enjoy!) where not going full-nuts on the roll crimp has wildly affected how the round builds pressure and ultimately fires. To say that not enough crimp "negatively affected ignition" is a genuine understatement.
I have personally found however, when you get in to the big stuff, you've got to get downright hardcore with the crimp. .460 S&W Magnum at 60,000 PSI. Yes, for sure the other rounds wish to lurch under recoil, but I've also had examples (more than I enjoy!) where not going full-nuts on the roll crimp has wildly affected how the round builds pressure and ultimately fires. To say that not enough crimp "negatively affected ignition" is a genuine understatement.
You will never get maximum fps with a taper crimp with a full load
in the 357 Magnum with a jacketed bullet, than if you used a
roll crimp in its place.
I can also increase the crimp on my lead bullet loads to squeeze out
the most fps out of my slow powders, if I need it.
Not saying a taper will not work for light target loads, though.
in the 357 Magnum with a jacketed bullet, than if you used a
roll crimp in its place.
I can also increase the crimp on my lead bullet loads to squeeze out
the most fps out of my slow powders, if I need it.
Not saying a taper will not work for light target loads, though.
rockquarry
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I don't doubt what you are saying. I loaded lots of .357 Magnum and .44 Magnum for more than forty years, but never loaded any of the larger high-pressure handgun cartridges, so can't comment on those. A "minimal crimp" with such cartridges would likely be a pretty stout crimp.
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