Crimping SWC

[posigian]

I am currently working on reloading some 38 special rounds using SWC and this is my first time using lead or SWC.

My question is where to I crimp? Do I crimp in the cannelure grove or at the tiny grove located near the top just before the “point”? If I crimp it in the cannelure grove it causes the cartridge to be over the maximum length.

I am using GFL brass, CCI 500 primers, 4.2 grains of Unique, and Speer 158 gr SWC.

Any other advice about reloading with lead would be greatly appreciated.

Thanks much,

 

[capbuster]

It makes it nice if your crimp,your bullet grove and you required overall lenght work out but its not always the case.I would imagine you are using a roll crimp. With the SWC bullet I would chose the overall lenght required and crimp away. Yes this will bit into the lead bullet a wee bit but if your crimp is consistent and not too heavy you should not have a problem.

 

[yankytrash]

Why crimp?

Crimping has been found to actually decrease accuracy due to a bullet leaving the casing at an angle, so-to-speak.
Picture this -
A crimped bullet with a typical medium charge of powder (like the one you are using). As you raise the gun, the shells are horizontal. The powder inside the bullet is sitting on the bottom of the casing. You pull the trigger, and the primer ignites, causing pressure build-up. The immediate location of the pressure is in the center of the casing, because of the primer, and causes a high pressure area. This pressure also fills the empty area of the casing, at the top of the shell. Then the powder ignites at the bottom of the casing. The immediate result of this more extreme pressure is to dislodge the bullet, whether crimped or not. The bullet is now leaving the casing.

If the shell has been crimped, the bullet is first going to choose the path of least resistance. That could be an area of the casing mouth that has weakened due to multiple reloads or a higher lead content on one point of the bullet. The bullet will leave through there first, causing the bullet to enter the chamber slightly cock-eyed. The remaining burning powder pushes the crooked bullet through the rifling twist, slamming it on the sides of the barrel repeatedly as it exits.

If the shell has not been crimped, you are almost eliminating the variable of the metals' weak spots. The entire bullet is allowed to 'slide' out of the casing, as opposed to 'popping' out of there like a champagne cork. That gives more consistent loads, thus more accurate loads.

Crimping variables can only be reduced by using new bullets in new casings, like the big boys do.

Just give that a thought. Try it out, too, for your own piece of mind. Use brass that's been reloaded a few times, and load ten crimped and ten not crimped. Shoot from a bench-rest position, and you'll see what I mean.

This applies even more to heavier bullets and charges.

 

[Bob C]

Crimp in the tiny groove located near the top just before the tip.

 

[labgrade]

Part of the reason to use a goodly crimp in revolvers is to keep the bullets from being pulled out during recoil - it's essentially an inertia bullet puller & the #6 bullet gets "hit" 5 times.

Ran into an interesting "problem" when loading cast SWCs for a Python & S&W 19/66. Python's chamber was shorter & I had to crimp over the first driving band & for interchangability, same for the 19/66.

I'd rather have crimped just below (as supposed to) driving band.
Ended up trading off the Python, so ....

Although the COAL does have some to do with pressures, it's also a SAAMI spec so that round will chamber in all firearms of that caliber. Check to see what fits in yours & load accordingly.

 

[Big Lou]

I mostly agree with the other postings. Here's some additional clarification.

If I'm using soft swaged SWC (like the Speer), I try to keep the velocities in the 800-900 fps range to avoid leading problems. I seat the bullet based on OAL (regardless of where the groves are) and then adjust the crimp die just so that it takes the flare out (essentially no crimp). Since these are such light loads, I don't have to worry about recoil impact on the other bullets.

Now if I'm shooting cast SWC at higher velocities (usually 1000-1200 fps), I still seat the bullets based on OAL (regardless of where the groves are) but at these levels, I find that you need to use a light crimp to secure the bullets during recoil.

If you are using even hotter loads, the recoil will become a greater factor and you may need a little heavier crimp. Also note that if you go to a slow burning powder (Like Hogdon H110 or Winchester 296), a heavy crimp is necessary to insure proper burning of the powder.

Hope this helps!

 

[WESHOOT2]

HANDGUNS

Crimp your ammo. Use Redding Profile Crimp die for straight-wall revolver cartridges; use LEE Carbide Factory Crimp die for semi-auto cartridges.