Crimping

skookumchuck

skookumchuck

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Brand new to reloading and I'm not sure about crimping rounds. I've got a Lee hand press to see if I enjoy this aspect before dropping bigger dollars on a progressive. I've started with .357 magnum and I'm unsure that they're crimped properly. I'm going to invest in the fourth die, factory crimp, but for now would the 50 rounds I've loaded be safe to fire in a revolver?
Thanks for any help you can offer.
 
If the bullets aren't crimped properly, the recoil can act like a big inertia bullet puller. The bullets can slowly move forward out of the case, potentially far enough to tie up the gun. That's the main reason for crimping for a revolver. Post some pics and somebody can likely give you an opinion on your crimp, or just shoot them and watch for any problems.
 
Pistol rounds I do not crimp, but rounds that go into my Levers actions I do. ( 30-30 and 45-70) just do I know the bullet wont push in.

I did score a deal at a local auction on many crimping dies, so now I will expand to 270 and 30-06.
 
Like others, I don't crimp everything I reload.
The ones that get a crimp are the ones for an auto-loader of some sort. The exception is the 44Mag; all of those get crimped, because of the bullet puller effect. I've even had some 44 Special loads work their way out of the case.
 
For roll crimps on revolver cartridges, there should be just enough crimp to roll the case mouth into the cannelure on the bullet. The outside of the case mouth should end up more or less flush with the bullet.

The rounds you reloaded are likely safe to shoot if they fit into the cylinder. Under-crimping could cause the bullets to pull out of the case under recoil and tie up the cylinder. Over-crimping can bulge the case and/or cause inaccuracy due to excessive bullet deformation.
 
With 357 or 44 mag, you crimp just enough to keep the bullets from moving forward under recoil. Even so, when I was shooting silhouette with big revolvers, I, like many of the shooters, always carried a short doweling and some type of light hammer, so if a bullet moved forward and tied up the cylinder, we could get out the dowel and tap the bullet back, so the cylinder would turn, and still not run out of the allotted time for that segment of the shoot.
 
H4831 said:
With 357 or 44 mag, you crimp just enough to keep the bullets from moving forward under recoil. Even so, when I was shooting silhouette with big revolvers, I, like many of the shooters, always carried a short doweling and some type of light hammer, so if a bullet moved forward and tied up the cylinder, we could get out the dowel and tap the bullet back, so the cylinder would turn, and still not run out of the allotted time for that segment of the shoot.
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did you find you had better accuracy with a light crimp vs a heavy crimp?
 
Spawn-Inc said:
did you find you had better accuracy with a light crimp vs a heavy crimp?
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No difference, heavy or light.
The reason for the light crimp is to help preserve case life. The 44 mag cases end their useful life by getting short, virticle cracks in the neck. Thus, to get best life for the brass, you bell the neck the very least you can, in order to get the bullet in without shaving lead and you crimp as little as what will usually hold the bullet.
 
I only crimp to take the flare down. I suspect that's what's happened to you. If you're loading jacketed bullets, you'll get away with less flare, if not any. I load lead exclusively and need to flare a little more due to the slightly larger diameter. If you look at factory rounds, they're all crimped. I'd say it for sure doesn't hurt if there's a cannelure there anyways.
 
Stout .357 loads require a good roll crimp. The roll crimp provides consistent bullet pull, such as you would get with consistently sized bottle neck case necks. Belling or flaring the case mouth to seat bullets is necessary, but one must be very judicious here. Too much fare just reduces case life, too little causes problems seating the bullet. Cast bullets require more flare than jacketed, but even jacketed bullets need some flare, or they will catch on the case mouth and crunch your case. That equals zero case life, which is not a good thing!
Roll crimp should always be into a cannelure on the bullet. Crimping into the jacket can cause jacket separation, and crimping into a cast bullet just deforms the bullet.
 
H4831 said:
A word of advice here. Don't reload cartridge #2, until you confirm that cartridge #1 fits your gun!
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A variation on Bruce's words of wisdom: make up a couple of dummy rounds (no primer or powder) to check fit and function.
 
Just to clarify, I was not intimating anyone should see if a loaded cartridge fits, by loading it in your rifle in your reloading room! At one time I would just go upstairs, tell my wife if she hears a big boom, to not worry, it will be OK. Then I would step out of my basement door, point the rifle at the ground in front of me and let the Mauser controlled feed pick my newly created cartridge from the magazine, chamber it and fully close the bolt. However, I ended that practice about twenty years ago.
Best, and surest procedure is to make a dummy reload, no primer or powder, exactly like you have, or will, make your reloads. With the dummy cartridge in the chamber and the bolt fully closed on it, you still will want to know how far the bullet is seated from the rifling. Here is an old time hand loaders method of determining this.
With the bolt fully closed on your dummy load, slide a wooden doweling, or cleaning rod with a blunt end, into the barrel until it touches the bullet on the dummy load. Put a mark on the rod at the end of the barrel.
Remove the dummy load, and take the bolt out. With the rifle pointed down, drop one of the bullets you are using into the chamber. The rubber end of a lead pencil works perfect to push up against the base of the bullet, pushing the bullet firmly against the rifling. With the rifle again horizontal, slide your doweling into the barrel again, until it touches the point of the bullet being held by your pencil. Mark the dowel. The difference between the two marks will be how far the bullet seated in your dummy load is from the lands.
To get the most exact reading from this procedure, it is best to use a wooden dowel and do the marking with a sharp, flat bladed knife, held flat against the end of the barrel. This will give you a very precise distance of how far the seated bullet is away from the lands.
Bruce
 
for the semi-auto folks, you will find reloading for revolvers a little different than your normal loads. I think because all the rounds are in the cylinder, each time you fire off a round, it acts a little like an impact bullet puller. In a semi-auto, the rounds are isolated in the mag from the majority of the recoil. Here's a pic of my normal 9mm semi-auto reloads fired from my S&W 929 (PF was only ~125 - normally 132 in my semi-auto). The 8th round had crept ~.060 after 7 rounds fired.

P7160002a.jpg

I couldn't find 9mm bullets with a crimp groove, but did switch to a Lee Factory Crimp die set - set at .378 and don't have a this problem anymore. I'm setting up Lee Factory Crimp dies now to reload 40S&W and 45acp for my S&W 610 and 625. Those will be reloaded to major power factor, so will see if this will be enough for them, or if I have to look for bullets with crimp grooves.

All these revolvers head space off of moon clips, so I don't have to worry about head spacing off of the rim of the cartridge like for my semi-autos.
 

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Did your bullets have a cannelure? If you roll crimped the case mouth onto the side of a bullet that doesn't have a cannelure you will buckle case or too much roll crimp even with a cannelure could make the case mouth too wide to chamber.
 
Greenjoytj said:
Did your bullets have a cannelure? If you roll crimped the case mouth onto the side of a bullet that doesn't have a cannelure you will buckle case or too much roll crimp even with a cannelure could make the case mouth too wide to chamber.
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No, I couldn't fine any 9mm bullets with a cannelure or crimp groove, so that's why I'm sticking with a taper or factory crimp.

Will probably have to do the same for reloading 40S&W/10mm and 45acp for my revolvers as those are semiauto bullets. I may be able to get away with a 45 Colt projectile, but I'm not finding any that are a round nosed profile. Doing a quick reload with a moon-clip full of flat nosed bullets is not a lot of fun lol
 
H4831 said:
With the dummy cartridge in the chamber and the bolt fully closed on it, you still will want to know how far the bullet is seated from the rifling. Here is an old time hand loaders method of determining this.
With the bolt fully closed on your dummy load, slide a wooden doweling, or cleaning rod with a blunt end, into the barrel until it touches the bullet on the dummy load. Put a mark on the rod at the end of the barrel.
Remove the dummy load, and take the bolt out. With the rifle pointed down, drop one of the bullets you are using into the chamber. The rubber end of a lead pencil works perfect to push up against the base of the bullet, pushing the bullet firmly against the rifling. With the rifle again horizontal, slide your doweling into the barrel again, until it touches the point of the bullet being held by your pencil. Mark the dowel. The difference between the two marks will be how far the bullet seated in your dummy load is from the lands.
To get the most exact reading from this procedure, it is best to use a wooden dowel and do the marking with a sharp, flat bladed knife, held flat against the end of the barrel. This will give you a very precise distance of how far the seated bullet is away from the lands.
Bruce
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That is a very nice trick, thanks Bruce. I've been trying to figure the throat of a 9mm Cx4 Storm using the "plunk" method, but when I dropped an over-long (2" OAL) test cartridge in the chamber (fired once, not resized and not crimped) and pulled it out... it was still 2" long. Your method might just give me the answer I was looking for, thanks! :)
 
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