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SBray 12-02-2012 13:11

Proper Crimping?
 
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I have just set my Dillion 550B up for 115 grain 9mm plated bullets. I took one apart to check the crimping I had applied and found the bullet had a slight ring around it. I have included two photos of the removed bullet and a finished one to show the amount of crimping I applied.

When I took this one apart, it separated with the first strike of the plastic hammer tool, suggesting that it wasn't over crimped. I did however see the slight indentation ring.

The finished bullet doesn't appear to have the edge of the case crimped anymore that what was necessary to remove the bell.

Does this appear to be properly crimped?

Any constructive suggestions would be appreciated!

Thanks,

Steve

F106 Fan 12-02-2012 13:27

In my view it is overcrimped. There really should be a mark on the bullet.

In the case of jacketed bullets, damage to the bullet itself isn't an issue although it would be for plated bullets.

The big problem is that the bullet pulled out on the first impact. Of course you might have made a mighty blow but I usually take 2 or 3 impacts to release a bullet. When you overcrimp the bullet, you take a chance of decreasing neck tension and that tension is what holds the bullet in place.

So, I would back off on the crimp and see if it doesn't take a little more effort to remove the bullet.

One thing you want to avoid is so little neck tension that the bullet sets back while chambering. This will increase chamber pressure and that's not a good thing.

Are you using a separate taper crimp die?

Richard

F106 Fan 12-02-2012 13:31

I guess I forgot to include the standard discussion of crimping pistol ammo. There isn't supposed to be ANY crimp on a cartridge that headspaces on the case mouth. This would include 9mm, 40 S&W, 45 ACP, etc. Heavy revolver cartridges are often crimped. Light revolver cartridges like .38 SPL HBWC target loads might not get a crimp.

All you want to do is remove the belling. If there is bell remaining, the rounds probably won't chamber. If you overdo it, you crimp the bullet. You don't want either.

You just want the case mouth closed up.

They really should call the process step something like "Removing The Bell" instead of "Crimp". There is no crimp!

Richard

Arc Angel 12-02-2012 13:42

You want that ring; however, you've got just a little bit too much of a compression crimp there. Back off the die by about 1/8th turn.

fredj338 12-02-2012 13:44

You do NOT want that ring, waaaaaay too much crimp. If you measure the shank of the bullet, you'll find it's probably around 0.350"! Poor accuracy & possble plating separation will occure. The crimp should not be visible on the outside & the bullet should not have any reduction in dia when you pull one down.
Your observation on the ease of pulling is actually backwards. Over crimping can REDUCE neck tension, as the case springs back a bit & the now undersized bullet comes free. You just want to remove the case mouth flare/bell, no more. A taper crimp does NOT hold the bullet in place, just finishes off the seating process.

dhgeyer 12-02-2012 13:46

I test it with a vernier caliper. I measure the diameter of the case just below the part that was belled, but still on where the bullet is. Then I measure the part that was belled, right up at the case mouth. I want them to be the same. I take several measurements on a few finished rounds.

SBray 12-02-2012 14:01

I'll take some measurements and make adjustments. No sense in loading anymore until I have got it correct, thanks!

Steve

WeeWilly 12-02-2012 14:14

Just back the crimp off until you have no bell and no line on the bullet.

Crimping removes neck tension. Bullets are softer than brass. When you crimp down the case goes into the bullet and springs back slightly, while the bullet springs back less, thus reducing neck tension. This is a widely misunderstood area of reloading.

njl 12-02-2012 14:27

Assuming you're using sorted by headstamp brass, measure the thickness of the brass at the neck. Measure the max width of your bullets. Adjust your crimp such that it's bullet width + 2x brass thickness. If you do that, you should not put a ring around the bullet.

F106 Fan 12-02-2012 15:07

But nobody separates pistol brass. :whistling:

So it's a compromise because not only does case wall thickness affect the diameter but case length affects the amount of crimp.

Richard

fredj338 12-02-2012 15:19

Quote:

Originally Posted by WeeWilly (Post 19692236)
Just back the crimp off until you have no bell and no line on the bullet.

Crimping removes neck tension. Bullets are softer than brass. When you crimp down the case goes into the bullet and springs back slightly, while the bullet springs back less, thus reducing neck tension. This is a widely misunderstood area of reloading.

I think I said that WW.:dunno::wavey:

fredj338 12-02-2012 15:20

Quote:

Originally Posted by njl (Post 19692272)
Assuming you're using sorted by headstamp brass, measure the thickness of the brass at the neck. Measure the max width of your bullets. Adjust your crimp such that it's bullet width + 2x brass thickness. If you do that, you should not put a ring around the bullet.

That bullet has been reduced in size, has little to do with mixed brass. There just isn't that much variation in brass thickness to cause that much reduction. No, it's just over crimped. I have alos NOT seen enough case lenght variation in service rounds to worry about the taper crimp. Again, the crimp just finsihes the seating. Over doing it does nothing good & several bad things.

Arc Angel 12-02-2012 16:00

I think we're going to have to agree to disagree. If the brass is chamfered in the way that it should be then you don't have to be fanatical about either case wall thickness or over crimping.

Too tight crimps do cause some of the jacket, accuracy, and deformity problems described above; but what's being considered, now, is crimping that is obviously way too tight. You'd have to be squeezing the dickens out of the bullet.

Over the years I have crimped tens of thousands of semi-auto bullets into cases while leaving a slight compression ring around the bullet. Never had any sort of problem with the ammunition. In fact I've got several thousand rounds of my own semiautomatic (compression crimped) ammunition in storage, right now.

Somewhat ironically Lee, 'factory crimp' dies can, and sometimes do, apply too much pressure to the bullet; and an over compressed bullet can loosen itself up making it almost impossible to safely use that bullet.

The easy way to test whether or not your crimps are, at least, adequate is to take a couple of finished rounds, and press them one at a time, and bullet first, into a bathroom scale. If the bullet doesn't set back before you reach 25 to 30#'s of downward pressure, then for most semi-autos you've done it right.

SBray 12-02-2012 16:20

Quote:

Originally Posted by Arc Angel (Post 19692564)
I think we're going to have to agree to disagree. If the brass is chamfered in the way that it should be then you don't have to be fanatical about either case wall thickness or over crimping.

Too tight crimps do cause some of the jacket, accuracy, and deformity problems described above; but what's being considered, now, is crimping that is obviously way too tight. You'd have to be squeezing the dickens out of the bullet.

Over the years I have crimped tens of thousands of semi-auto bullets into cases while leaving a slight compression ring around the bullet. Never had any sort of problem with the ammunition. In fact I've got several thousand rounds of my own semiautomatic (compression crimped) ammunition in storage, right now.

Somewhat ironically Lee, 'factory crimp' dies can, and sometimes do, apply too much pressure to the bullet; and an over compressed bullet can loosen itself up making it almost impossible to safely use that bullet.

The easy way to test whether or not your crimps are, at least, adequate is to take a couple of finished rounds, and press them one at a time, and bullet first, into a bathroom scale. If the bullet doesn't set back before you reach 25 to 30#'s of downward pressure, then for most semi-autos you've done it right.

Interesting way of testing!

I have become, perhaps overly cautious, when considering how thin the plating is on these types of bullets. The ones I initially damaged months ago, had the plating surface broken so as to reveal the lead. The ones I have just posted about were just slightly dented, so as to form a ring that I could barely feel.

In an effort to obtain my best results, not just for safety, but accuracy, I will take everything suggested by all of you into consideration and continue to work at the final settings.

Thank you,

Steve

WiskyT 12-02-2012 16:25

I don't know if the crimp is causing his problem as much as the bullet might be getting sized down by the case. The crimp, in the picture, as far as I can tell, looks to be about right. Plated bullets are pure lead. They are softer than dog**** with a nearly microscopic coating of copper on them, which isn't exactly strong either. Some plated bullets are more stout than others, like Gold Dots, but generally, cheap bulk plated bullets are like gummy worms.

A short, stiff, 9mm case can squeeze down soft bullet. I would seat a couple and not crimp them at all. Pull those and see if they look like those Hebrew bullets.

Arc Angel 12-02-2012 16:58

Quote:

Originally Posted by WiskyT (Post 19692661)
I don't know if the crimp is causing his problem as much as the bullet might be getting sized down by the case. The crimp, in the picture, as far as I can tell, looks to be about right. Plated bullets are pure lead. They are softer than dog**** with a nearly microscopic coating of copper on them, which isn't exactly strong either. Some plated bullets are more stout than others, like Gold Dots, but generally, cheap bulk plated bullets are like gummy worms.

A short, stiff, 9mm case can squeeze down soft bullet. I would seat a couple and not crimp them at all. Pull those and see if they look like those Hebrew bullets.

Yup, I was thinking that; but, I still think that the crimp I'm looking at in the original pictures is ever so slightly too tight. You want to leave a line; but, what you don't want to see is any bullet material bulging just ahead of the crimp line.

The majority of semi-auto bullets I've ended up pulling had some sort of line or other evidence that they were pulled bullets - including factory ammo. After thinking about it I'm going to agree that some thinner walled cases do leave fewer marks on a bullet. As memory serves me it's been a very long time since I've had a bullet set back in a pistol (any kind of pistol).

Then again, I've always applied one of those crimps that after you've run a hundred rounds or so through the press you get a little of that brass, 'fairy dust' starting to show up. On untrimmed pistol ammo whenever I saw that dust I knew the crimps were coming out right.

dhgeyer 12-02-2012 17:22

Quote:

Originally Posted by dhgeyer (Post 19692148)
I test it with a vernier caliper. I measure the diameter of the case just below the part that was belled, but still on where the bullet is. Then I measure the part that was belled, right up at the case mouth. I want them to be the same. I take several measurements on a few finished rounds.

I think you guys are overthinking this. I'm quoting myself so as to repeat this way of doing it, but I'll elaborate.

Steve, go back and read the directions for setting up the taper crimp die in the Dillon 550. It says, to paraphrase, start with the ram in the up position (handle down) with a seated bullet in the crimp die, and the crimp die not touching the case. Screw the crimp die down so that it is touching the case. Move the ram down (raise the handle), and screw the die down a little. Push the handle down and make the crimp. Take the round out and check it. Continue screwing the die down 1/8 turn at a time till you get the crimp you want. When you get the crimp you want, tighten the lock nut with the round in the die and the handle down.

Now, if when you are checking the crimp each time, you do it with the caliper (vernier or dial) as I described above, you will get a perfect crimp, which is really a non-crimp.

You want the case straight. Damage to the bullet isn't the only issue. These cases headspace on the case mouth. You don't want to risk the case being too narrow at the mouth to headspace properly.

I think if you hold a straight edge against a factory round, or do the caliper test I described, you will see that they are just as I describe. I just measured 3 different brands of factory rounds, several cartridges each. They all measured .375 (plus or minus half a thousandth) just behind the case mouth and at the case mouth. None of them measured different behind the case mouth from at the case mouth. No crimp. Straight case wall right out to the mouth. That's what the factories do - that's what you should do.

smokin762 12-02-2012 17:40

I just started reloading myself. I have the Dillon 650.

One of my first problems was I was belling the case mouth too much. The crimping die didn’t seem to want to overcome this. Since, I started just making the bell big enough for the bullet to set on the case to align with the seating die. Everything seemed to work out from there on. :dunno:

fredj338 12-02-2012 19:22

Quote:

Originally Posted by Arc Angel (Post 19692564)
The easy way to test whether or not your crimps are, at least, adequate is to take a couple of finished rounds, and press them one at a time, and bullet first, into a bathroom scale. If the bullet doesn't set back before you reach 25 to 30#'s of downward pressure, then for most semi-autos you've done it right.

Taper crimp does NOT hold the bullet in place, proper neck tension does. SO setback testing isn't telling you much about the crimp. If you deform the bullet during crimping, it's over crimped & little good comes from that. If a pulled bullet shows that much deformation, you aren't helping your accuracy a bit, maybe not reliability either, as you can cause loss if critical case neck tension.
A faint line is acceptable, reducing the bullet dia is not. Easy enough to check, pull a bullet & measure the part inside the case. I have pulled WWB ammo that looks like that, maybe why WWB is never all that accurate. Undersized driving bullets are never going to shoot well.:dunno:

fredj338 12-02-2012 19:24

Quote:

Originally Posted by smokin762 (Post 19692898)
I just started reloading myself. I have the Dillon 650.

One of my first problems was I was belling the case mouth too much. The crimping die didnít seem to want to overcome this. Since, I started just making the bell big enough for the bullet to set on the case to align with the seating die. Everything seemed to work out from there on. :dunno:

Then you were NOT setting the crimp die properly. There is no case flare that can not be removed w/ a proper roll or taper crimp. Case flare has nothing to do with final crimp.


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