38 spl crimp ?
- Thread starter rebs
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g.willikers
New member
The bullet determines the crimp, the type, how much, and where it goes.
If the bullet depth is suitable to roll the case mouth into the cannelure, that's where it should go.
If, for some reason, the mouth of the case doesn't align with the cannelure, then you might need a very light roll or even a taper crimp elsewhere on the bullet.
The same for a smooth sided plated or jacketed bullet that doesn't have an actual cannelure on the case.
One reason for the misalignment of cannelure and case mouth might be from adjusting the round overall length, for example, to the cylinder length and distance from the barrel.
Like when using .38s in a .357.
Life is so confusing.
If the bullet depth is suitable to roll the case mouth into the cannelure, that's where it should go.
If, for some reason, the mouth of the case doesn't align with the cannelure, then you might need a very light roll or even a taper crimp elsewhere on the bullet.
The same for a smooth sided plated or jacketed bullet that doesn't have an actual cannelure on the case.
One reason for the misalignment of cannelure and case mouth might be from adjusting the round overall length, for example, to the cylinder length and distance from the barrel.
Like when using .38s in a .357.
Life is so confusing.
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Rule of thumb; if a bullet has a crimp groove or cannalure, use a roll crimp. If the bullet is smooth sided, use a taper crimp. There will be exceptions posted, but for new reloaders this ROT works. Three grains of Bullseye is a fairly light load so not a lot of crimp will be needed (some fellers loading wadcutters, very little and sometimes no crimp is used.). If you're looking for how much crimp, compare with a factory round using the same/similar bullet...
I have a Lachmiller mold that drops 160 gr. SWC and for .38 loads I use W231 and Universal upper loads with a "medium to heavy" crimp.
I have a Lachmiller mold that drops 160 gr. SWC and for .38 loads I use W231 and Universal upper loads with a "medium to heavy" crimp.
"...with 3.0 of Bullseye..." That is a wee tick below current minimum. Not enough to matter. Max is 3.5. Minus 10% is 3.1. Close enough. Shouldn't need any crimp.
The amount of crimp isn't determined by the bullet at all. Velocity and the firearm decide if and how much crimp is required. Hot loads need a crimp, but as little as possible. Just enough to keep the bullet in place. Ditto for ammunition used in a lever action.
"...The bullet determines the crimp, the type..." Where the cartridge headspaces determines the type of crimp. No roll crimps in a straight walled pistol cartridge. Those headspace in the case mouth. Rimmed cartridges are more forgiving and don't really care.
"...Life is so confusing..." Yep and then they tax you and throw dirt in your face. snicker.
The amount of crimp isn't determined by the bullet at all. Velocity and the firearm decide if and how much crimp is required. Hot loads need a crimp, but as little as possible. Just enough to keep the bullet in place. Ditto for ammunition used in a lever action.
"...The bullet determines the crimp, the type..." Where the cartridge headspaces determines the type of crimp. No roll crimps in a straight walled pistol cartridge. Those headspace in the case mouth. Rimmed cartridges are more forgiving and don't really care.
"...Life is so confusing..." Yep and then they tax you and throw dirt in your face. snicker.
If the cartridge head spaces on the case mouth, whether bullets have cannelure or not, do NOT roll crimp.
If bullet does not have a cannelure or crimp groove, roll crimping can damage the bullet and you'll have to use a taper crimp and keep pressure/velocity low.
You'll have to find out how much roll crimp you and your gun need.
I prefer Redding Profile Crimp dies for all roll crimping. For me, they just make more accurate loads than the other roll crimp dies I have used.
I found back around 1974 that my reloads were more accurate if I separated seating and crimping. I seat so the case mouth is just below the top of the cannelure or crimp groove and then crimp the case into the cannelure/groove.
If I am shooting very light target loads (normally, 148gn L-HBWC), all I need is a very slight curve to the case mouth. For standard .38 Spl loads, I need a roll that is easily seen. For full-house .357 Mag loads, I need a roll that is VERY pronounced, but does not dig into the bullet at all.
this is a lot like asking someone how much they turn the steering wheel to make a right turn--you just learn how much to turn the wheel by doing and NOT by having someone say that you turn the wheel 1 1/2 complete turns or whatever.
If bullet does not have a cannelure or crimp groove, roll crimping can damage the bullet and you'll have to use a taper crimp and keep pressure/velocity low.
You'll have to find out how much roll crimp you and your gun need.
I prefer Redding Profile Crimp dies for all roll crimping. For me, they just make more accurate loads than the other roll crimp dies I have used.
I found back around 1974 that my reloads were more accurate if I separated seating and crimping. I seat so the case mouth is just below the top of the cannelure or crimp groove and then crimp the case into the cannelure/groove.
If I am shooting very light target loads (normally, 148gn L-HBWC), all I need is a very slight curve to the case mouth. For standard .38 Spl loads, I need a roll that is easily seen. For full-house .357 Mag loads, I need a roll that is VERY pronounced, but does not dig into the bullet at all.
this is a lot like asking someone how much they turn the steering wheel to make a right turn--you just learn how much to turn the wheel by doing and NOT by having someone say that you turn the wheel 1 1/2 complete turns or whatever.
Poor guy is probably thoroughly confused.
38 special does NOT headspace on the case mouth, AND You don't have to decide whether to use a roll crimp or a taper crimp. Just use the crimp die that came with your die set. It has served me correctly 100% of the time for more than 30 years. It will make the right type of crimp for the round you are loading.
38spl with SWC is about as basic and classic as you can get.
Answer is "maybe". Try some with just enough crimp to remove the flair, a lightly visible crimp, and a heavier crimp, and then tell us which gives YOU the tightest group. Results will be unique to your load and your gun.
38 special does NOT headspace on the case mouth, AND You don't have to decide whether to use a roll crimp or a taper crimp. Just use the crimp die that came with your die set. It has served me correctly 100% of the time for more than 30 years. It will make the right type of crimp for the round you are loading.
38spl with SWC is about as basic and classic as you can get.
Answer is "maybe". Try some with just enough crimp to remove the flair, a lightly visible crimp, and a heavier crimp, and then tell us which gives YOU the tightest group. Results will be unique to your load and your gun.
g.willikers
New member
Too much crimp, especially a roll crimp, can actually result in a loose fitting bullet that can rock around inside the case.
The place on the bullet where the crimp works can act like a fulcrum.
What the effect on accuracy would be depends on other factors, too.
Like how well the bullet centers on the forcing cone of the barrel, the fit of the bullet to chamber and barrel, 'etc.
And, of course, what is meant by "accuracy."
The devil is in the details.
Fulcrum? Yes, you're right, if the bullet has a deep, sharp crimp groove, that could conceivably loosen the brass a bit at the area behind the crimp, but I'm darned if I know what the results would be.
I'm probably in the minority here, but I believe that hitting the forcing cone will stabilize burn and ignition, and lock the bullet into alignment. In a lot of cases, a crimp is the right thing to do, in some, it should be heavy, others moderate or light, but I don't really believe that a handgun should be left uncrimped. A crimp is needed to insure that the bullet remains stable in any sort of handling and during firing. It provides another level of consistency in shooting by adding consistency to ignition.
I see so many people who say that crimping in many cases is unnecessary and therefore, should not be done, but nobody has ever given a particularly Good explanatio for not crimping. It just begs the question, why should a person leave a handgun bullet with nothing but a friction fit, and hope t h at nothing goes wrong?
Unless there is a sound, solid reason to not use a crimp, since there are many reasons to do so, I believe that in even low power loads, a person should at least press the case mouth solidly to the bullet.
I'm probably in the minority here, but I believe that hitting the forcing cone will stabilize burn and ignition, and lock the bullet into alignment. In a lot of cases, a crimp is the right thing to do, in some, it should be heavy, others moderate or light, but I don't really believe that a handgun should be left uncrimped. A crimp is needed to insure that the bullet remains stable in any sort of handling and during firing. It provides another level of consistency in shooting by adding consistency to ignition.
I see so many people who say that crimping in many cases is unnecessary and therefore, should not be done, but nobody has ever given a particularly Good explanatio for not crimping. It just begs the question, why should a person leave a handgun bullet with nothing but a friction fit, and hope t h at nothing goes wrong?
Unless there is a sound, solid reason to not use a crimp, since there are many reasons to do so, I believe that in even low power loads, a person should at least press the case mouth solidly to the bullet.
"Normally" too heavy of a crimp will buckle/bulge the sides of the case, loosening the grip on the bullet and often interfering with chambering.
For a new reloader, just copy the amount you see on a factory round. Forum members answering new reloader's questions are usually experienced reloaders that often drift into "theory" or advanced reloading techniques, resulting in confusion for the new guy. Don't overthink crimping. You're just forming metal around/into a bullet. 99% of the time you won't screw up anything if you crimp "too much" or "too little". K.I.S.S.
Go slow, double check everything, and most important, have fun!
For a new reloader, just copy the amount you see on a factory round. Forum members answering new reloader's questions are usually experienced reloaders that often drift into "theory" or advanced reloading techniques, resulting in confusion for the new guy. Don't overthink crimping. You're just forming metal around/into a bullet. 99% of the time you won't screw up anything if you crimp "too much" or "too little". K.I.S.S.
Go slow, double check everything, and most important, have fun!
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.38 Special, light load, start with a light crimp, basically just enough to see/feel. Shoot a couple cylinders of 5 shots, leaving the same round unfired, each time. Then check it for bullet movement. If it hasn't moved, you're good to go.
If it has, increase the amount of crimp slightly, and repeat the test until there is no bullet movement. That's all the crimp you need for that load and that gun.
The gun DOES make a difference. A large frame heavy gun with .38 light loads might show no bullet movement with uncrimped/barely crimped rounds. Same rounds in a snub nose same light or no crimp and you could have serious bullet jump. Could. Only actual shooting with your guns and components assembled your way will show what actually will happen.
If it has, increase the amount of crimp slightly, and repeat the test until there is no bullet movement. That's all the crimp you need for that load and that gun.
The gun DOES make a difference. A large frame heavy gun with .38 light loads might show no bullet movement with uncrimped/barely crimped rounds. Same rounds in a snub nose same light or no crimp and you could have serious bullet jump. Could. Only actual shooting with your guns and components assembled your way will show what actually will happen.