357 crimp
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beatledog7
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I have only three factory .357Mag loads in my stock: Hornady, Federal, and Buffalo Bore, ranging from 140 to 180 grains. All have a very obvious crimp.
I use pretty light crimps on most of my loads.
I was just checking some crimps on my 'mid range' load, a 158 plated at 1,000 fps. I'm only using .003" crimp on them, barely visible, but it's enough. I put my emphasis on case neck tension.
I was just checking some crimps on my 'mid range' load, a 158 plated at 1,000 fps. I'm only using .003" crimp on them, barely visible, but it's enough. I put my emphasis on case neck tension.
Brad.
Member
I think that some factory loads use a taper crimp instead of a roll crimp...don't know why...Looking through what I got laying around PMC bronze 158 gr JSP no crimp but125 gr JSP Rem UMC taper crimp, 158 gr GDHP roll crimp, 158 gr fed Fusion HP roll crimp and of course all my reloaded 357 roll crimp. So there might be something to this I know that semi-auto couldn't drive this the Coonan 357 would headspace on the rim and the desert eagle has a fixed headspace. Probably comes down to machine set up and company safety requirements.
The crimp does very little as far as holding the bullet in place during recoil. The case neck tension does almost all of that job. Crimping the case mouth into a cannelure on the bullet helps some but case neck tension is still doing most of the work at preventing bullet movement. If the case neck tension is not correct you can crimp the round all you want and it will still fail to hold the bullet. In fact over crimping actually makes the situation worse. You don't "see" a lot of heavy crimps on most factory rounds today simply because the manufacturers have chosen a bullet with no cannelure in it. A tight taper crimp is all you're going to get in that case. With proper case neck tension a crimp is hardly needed. A bunch of old guys figured this out a very long time ago. On a semi auto cartridge the problem is setback upon feeding (or rechambering over and over) and on a semi auto round you cannot use a roll crimp because the round headspaces on the case's mouth. On a revolver the main problem is bullets pulling out of the case under recoil (especially with all of the extremely light revolvers marketed today). Neck tension is what you need. On a lot of mass produced factory ammo today the case neck tension is almost nonexistent - which is why you hear so much talk about bullet setback on semi auto rounds. If you handload you can easily solve the problem by making sure that you are not over expanding the case or using an undersized bullet. Unfortunately most of the U.S. ammo producers have decided that it's more important to sell large quantities of product than to make the best quality they can.
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rcmodel
Member in memoriam
I disagree.
A firm roll-crimp into a lead revolver bullet crimp groove or jacketed bullet cannulure goes very far in preventing bullet pull from recoil.
As well as providing more consistent powder burn start pressure when using slow burning magnum class powders.
Trying to taper-crimp a heavy magnum load in a light hard kicking gun will result in failure to keep the bullets from getting jerked out of the cases by recoil.
Why your factory loads show little or no roll crimp?
I have no idea.
But that just is not the way to do it.
rc
A firm roll-crimp into a lead revolver bullet crimp groove or jacketed bullet cannulure goes very far in preventing bullet pull from recoil.
As well as providing more consistent powder burn start pressure when using slow burning magnum class powders.
Trying to taper-crimp a heavy magnum load in a light hard kicking gun will result in failure to keep the bullets from getting jerked out of the cases by recoil.
Why your factory loads show little or no roll crimp?
I have no idea.
But that just is not the way to do it.
rc
Reefinmike
Member
Drail- I beg to differ... have you ever completely pulled the core out of a well crimped in place bullet? I have... several times. where the same bullet loaded with no roll crimp will pop out in two raps with the impact puller.
Op- the remingtons wont have a visible roll crimp if they are 125gr golden sabers as those do not have a cannalure. they may be taper crimped idk but they do have tar on the bullet which makes em a bear to pull... dont ask me how i know!
picture is of the stout roll crimp I use on my h110 magnums. the plated/hp38 loads just barely get a roll crimp on em, 38's get no crimp for me.
Op- the remingtons wont have a visible roll crimp if they are 125gr golden sabers as those do not have a cannalure. they may be taper crimped idk but they do have tar on the bullet which makes em a bear to pull... dont ask me how i know!
picture is of the stout roll crimp I use on my h110 magnums. the plated/hp38 loads just barely get a roll crimp on em, 38's get no crimp for me.
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41 Mag
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WIth most of my shooting being handguns I found out a long time ago that the case tension does most of the work, and the crimp settles the argument on the bullets actually moving. I have loaded top end loads in my 44 using 2400 and 296 with both 180 and 240gr bullets. In both cases and even now in my 454 I use only enough crimp to roll the lip of the case into the cannalure of the jacketed or groove in the cast bullets.
When I work up my loads I set up my die so that it will just hold the bullets in place under the full recoil of 10 rounds. I use a full cylinder and shoot each of the ive rounds while measuring the last after each shot. If it moves I adjust my crimp setting until it doesn't. At the point I have shot 10 rounds and it hasn't moved I call it good. If they haven't moved by then they usually aren't going to and they are usually shot before they get any more times through the cylinder than that.
I have also found that the amount of crimp put on a bullet can and does effect the accuracy of the load as well. Even with the slower powders like 296/110 and top end loads. What surprised me more was that I have had more issues with fast powders being more sensitive to this than the slower ones.
Also as mentioned some bullet will take a roll crimp some need a taper. Either one will work on a bullet with a groove, but the roll doesn't work so well on the ones without it. I used a taper on a LOT of my 357 loads when I first started loading it, simply due to that is what the die I have used. I have since added the roll crimp die as well and use them both for different loads.
When I work up my loads I set up my die so that it will just hold the bullets in place under the full recoil of 10 rounds. I use a full cylinder and shoot each of the ive rounds while measuring the last after each shot. If it moves I adjust my crimp setting until it doesn't. At the point I have shot 10 rounds and it hasn't moved I call it good. If they haven't moved by then they usually aren't going to and they are usually shot before they get any more times through the cylinder than that.
I have also found that the amount of crimp put on a bullet can and does effect the accuracy of the load as well. Even with the slower powders like 296/110 and top end loads. What surprised me more was that I have had more issues with fast powders being more sensitive to this than the slower ones.
Also as mentioned some bullet will take a roll crimp some need a taper. Either one will work on a bullet with a groove, but the roll doesn't work so well on the ones without it. I used a taper on a LOT of my 357 loads when I first started loading it, simply due to that is what the die I have used. I have since added the roll crimp die as well and use them both for different loads.
RealGun
Member
The 150 gr PMC that I bought has no roll crimp, but others may have. I crimp them myself before use. Unfortunately, I bought hundreds.
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