How to determine a proper crimp?

[IGOTGLOCKED]

I just adopted a 650 and am new to reloading by a couple of weeks. My question is how does one determine a proper crimp?

Thx!

[Sarge]

Depends on the round. Straight wall pistol cases get taper crimped. Translation= just enough to remove the bell and straighten the wall out

[N3WWN]

You can also look up the SAAMI specs for the cartridge that you are loading, which includes a mouth diameter range of the loaded round. That should get you close... or at least give you a starting point.

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[pointerman1967]

Take a look at the data for the round you are doing. There should be dimensions for the crimp that you can measure. Make sure you get this right. When I first started competing I shot and reloaded 45 ACP. Didn't have enough crimp and had a round get the bullet pushed back and the gun went BOOM when it should have went bang. Went home and cycled the rounds through the pistol twice by hand and the setback was visible. A little more crimp fixed the problem.

[GrumpyOne]

Take a look at the data for the round you are doing. There should be dimensions for the crimp that you can measure. Make sure you get this right. When I first started competing I shot and reloaded 45 ACP. Didn't have enough crimp and had a round get the bullet pushed back and the gun went BOOM when it should have went bang. Went home and cycled the rounds through the pistol twice by hand and the setback was visible. A little more crimp fixed the problem.

Setback is caused more by the brass not being sized right than the crimp.

[GrumpyOne]

To get the correct "crimp", use your calipers to measure the thickness of the case wall at the mouth (9mm is gonna be somewhere around .011), multiply that by 2, then add the diameter of the bullet you are using. Example : .011 x 2 = .022 + .355 = .374. This should be the measurement of the outside of the case mouth after the crimp.

[Reshoot]

In addition, I like to pull a bullet and visually inspect the crimp effect on said bullet.

[Hi-Power Jack]

If the cartridge won't slide into your chamber, it might be not "crimped"

enough.

If you start to lose accuracy, or the pulled bullets have a noticeable

"crimp mark" on them, you might be crimping too much.

If they slide into the chamber easily and are accurate, you're

probably doing good.

Edited March 4, 2016 by Hi-Power Jack

[pointerman1967]

Grumpy,

Well, my sizing die really isn't adjustable to my knowledge. It sits on a Dillon 650 so it's impossible to skip this step. After adjusting crimp I did the same test (racking rounds through the pistol a couple of times) and they did not end up with setback. Pretty sure this was a crimp problem.

[GrumpyOne]

Grumpy,

Well, my sizing die really isn't adjustable to my knowledge. It sits on a Dillon 650 so it's impossible to skip this step. After adjusting crimp I did the same test (racking rounds through the pistol a couple of times) and they did not end up with setback. Pretty sure this was a crimp problem.

Too much crimping (over crimping) causes the bullet, especially a lead or plated bullet, to be swaged to the size of the crimp. While the brass will spring back a bit, the lead projectile will not, which can, will, and does lead to setback. So, even though your sizing dies is not the culprit (your crimping die is the guilty one), it is because you resized the brass a bit with the crimp die.

[9x45]

Of course the only things that don't change on any press are the die dimensions. So every once in a while, a piece of brass comes thru with an ID that will let a bullet slip down in and more crimp won't fix that. Since tapered cases are more difficult to measure, as the OD changes with length, I use the "Wipe" method. Mark the round after the seat station, then check it after the crimp (really the de-bell station). Should wipe about .005" off. Then I check them in the kinetic bullet puller, takes 5 good whacks, but not deformation on the coated bullets.

[Sarge]

Grumpy,

Well, my sizing die really isn't adjustable to my knowledge. It sits on a Dillon 650 so it's impossible to skip this step. After adjusting crimp I did the same test (racking rounds through the pistol a couple of times) and they did not end up with setback. Pretty sure this was a crimp problem.

All dies are adjustable. Time to read up on basic reloading.

[MemphisMechanic]

On a 650, you loosen the lock ring holding the die into the press, screw it in or out a bit, and tighten the lock ring back down.

[Steve RA]

Once you set the "sizing die" properly you should never have to change the setting.

Think the reference was to seat/crimp die if only one or seat die and crimp die if two.

[Ray_Z]

I use the kiss method. I slide my fingers up the case " pistol cartridges ". If I can feel a flair at the mouth of the case, I will adjust the last station down an 1/8 of a turn until the case is smooth.

[ramairbrc]

I put a factory loaded round in the crimping station, with a loose die! I cycle the handle until the round is all the way up. I then rotate the die down until it touches the loaded round firmly. I then cycle the handle down, and adjust the die 1/8 of a turn further down and tighten the lock. I then cycle the handle back up (with the same round in the same station; on the 650, you'll have to manually insert it again) and watch the toolhead lift slightly, with the handle cycled fully. Then load a round and compare.

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Edited March 9, 2016 by ramairbrc