Had my first crimp jump

[Tech Ninja]

I have been working on a .38 Special load, 4.7 grains of American Select and an X-treme 125 plated bullet, crimped with a taper crimp die. These work great from a GP-100. But when I tried them in an LCR it locked up on the fifth round and I found a bullet rattling around in the cylinder. I loaded five more but only fired three, the remaining two looked like this:

No wonder that bullet pulled out on the first five rounds. But that's not surprising considering the weight difference of the guns. I was using a taper crimp die and I think I will switch back to a roll crimp die. Looks like I need a bunch more crimp.

 

[ArchAngelCD]

You are correct, the lighter gun is more likely to cause a bullet pull. Lighter bullets will pull sooner than heavier bullets, try a 158gr bullet instead or just go to a coated cast bullet and apply a normal roll crimp. You can probably apply enough a roll crimp on those plated bullets to prevent the pull without deforming the bullet or breaching the plating.

 

[243winxb]

Check the expander diameter. Should be .356"

 

[ljnowell]

You are correct, the lighter gun is more likely to cause a bullet pull. Lighter bullets will pull sooner than heavier bullets, try a 158gr bullet instead or just go to a coated cast bullet and apply a normal roll crimp. You can probably apply enough a roll crimp on those plated bullets to prevent the pull without deforming the bullet or breaching the plating.

My experience has been the opposite, that heavier bullets pull sooner, as their weight resists motion more upon recoil.

 

[TimSr]

Are you sure this is your first to jump, or just the first to jump far enough to lock it up? Cannelures and roll crimps make a nice combination.

 

[murf]

tech ninja,

suggest you push one of your loaded rounds down on a bathroom scale and find out how much weight it takes to move the bullet down into the case. from the look of your pic, you don't have enough case tension on that bullet.

murf

 

[joem1945]

When I set up dies for a new caliber, I'll mark each case with a number. I measure the OAL and record it. Then I fire 1 round at a time and measure the rest against the log. If any got longer I know my crimp is not holding.

 

[beag_nut]

Taper crimp is for autoloaders, and their equivalent calibers like 9mm. Roll crimp is for revolvers and their equivalent calibers, like .38 special, .357 mag, etc.
Roll crimp is much more effective at holding the bullet in place. Roll crimp should not be used in autoloaders since most rely on the front of the case for positioning the cartridge. Roll crimp is ideal for cartridges with a rear "flange", which locates the cartridge in the cylinder.

 

[Walkalong]

That is a plated bullet without a real cannelure, just marks. It needs a taper crimp. It can be crimped a bit more than he has done, but I believe he needs more neck tension.

Do as 243winxb has suggested, check the expander. Either the sizer is too big, the expander is too big, or some of both. Or, it's Remington brass and his sizer isn't tight enough for the thinner Remington brass.

http://www.thehighroad.org/showpost.php?p=7699828&postcount=14
.

 

[Tech Ninja]

Well it is Remington brass! Maybe that's the real problem, I'll have to experiment and see if other brass does the same.

 

[ljnowell]

Taper crimp is for autoloaders, and their equivalent calibers like 9mm. Roll crimp is for revolvers and their equivalent calibers, like .38 special, .357 mag, etc.

Roll crimp is much more effective at holding the bullet in place. Roll crimp should not be used in autoloaders since most rely on the front of the case for positioning the cartridge. Roll crimp is ideal for cartridges with a rear "flange", which locates the cartridge in the cylinder.

There are many situations where a taper crimp is best used on revolver rounds.

 

[rcmodel]

But there are none when used in a 13 oz. .38 Special revolver!!

That is clearly a heavy roll-crimp requirement right there.

rc

 

[ljnowell]

But there are none when used in a 13 oz. .38 Special revolver!!

That is clearly a heavy roll-crimp requirement right there.

rc

I agree, but I detest blanket statements like the one above.

 

[16in50calNavalRifle]

Walkalong, ljnowell, rc - please elaborate a bit on revolver loads for which taper crimp is appropriate, if you could. I have only used roll crimps so far, and I'm curious about applications of taper crimp for revolver ammo.

 

[ljnowell]

Walkalong, ljnowell, rc - please elaborate a bit on revolver loads for which taper crimp is appropriate, if you could. I have only used roll crimps so far, and I'm curious about applications of taper crimp for revolver ammo.

Using thinly plated bullets is a common one.

I load probably 10k+ per year of 38 specials with a taper crimp, literally no crimp I just smooth out the case mouth. I found quite sone time ago that when loading for accuracy, using small amounts of fast burning powder, that a roll crimp was detrimental to accuracy. All of my competition 38s are loaded this way.

 

[joneb]

This may be worth a look, http://leeprecision.com/357-magnum-custom-collet-style-crimp-die.html
I agree about the apparent lack of neck tension and I do not see a crimp mark on the bullets. Try some more crimp

 

[Grumulkin]

1. Does it REALLY matter if a bullet is deformed by crimping for loads shot in a revolver. I highly doubt there would be any noticible change in accuracy.

2. So what if bullet plateing is breached. I'll bet it's also breached when the bullet goes down the barrel.

3. Except for straight walled cases that need to headspace on the mouth of the case, I see no reason a taper crimp is better than a roll crimp.

The Lee Factory Crimp die is a great product. It's so great I had ones custom made for a 378 Weatherby and a 460 S&W Magnum both of which had bullets jumping the crimp even with a roll crimp as heavy as possible without buckeling the case.

 

[Walkalong]

That is a different type of crimp than roll or taper, and is a "stab" (?) crimp, but you are right, and I expect it would work well here, and Lee would be happy to make him one.

But in this application I think more neck tension and a heavier taper crimp, if even needed after getting sufficient neck tension, would work.

And while heavier bullets can be worse, they have more bearing surface inside the case as well, and it's just .38 Spl.

I bet with thicker brass, or a thinner expander, or both if is over sized now, his problem would go away.

 

[Walkalong]

Using thinly plated bullets is a common one.

Yep. Plated bullets which have no real cannelure, like the OP's, and these.

Medium Taper Crimp on an X-Treme 200 Gr FP in .44 Spl

Heavy Taper Crimp on a Powerbond 125 Gr HP in .357

 

[TimSr]

There you have it. Every possible suggestion made at least once. Start trying them all, and then come to your own concluion. The easiest ones to try that don't require buying special equipment should be tried first.

Try brass of a different mfg. Crimp as you did before and check for creep and accuracy.

Roll crimp some in the immitaion cannelure, breeching the plating and check for creep and accurracy.

Roll crimp some in the immitaion cannelure, without breeching the plating and check for creep and accurracy.

Taper crimp some in the immitaion cannelure harder than before, and check for creep and accurracy.

Buy a new resizing die.

Buy a larger slection of bullest to try.

Did I miss anything? Persoanlly, I think the 2nd and 3rd options will solve your problem, but why listen to a starnger on the interent? Your own research will give you an answer you can trust.

 

[ljnowell]

3. Except for straight walled cases that need to headspace on the mouth of the case, I see no reason a taper crimp is better than a roll crimp.

.

Accuracy. Unless it doesn't really matter to you.

 

[macgrumpy]

Walkalong - please define the difference between a real cannelure and an imitation cannelure. By definition a cannelure is just a series of cuts or grooves regardless of their depth so I don't understand how you define an imitation cannelure and what difference do you believe an imitation cannelure makes, what effect does it cause?

 

[murf]

a cannelure is a groove around the bullet. a "fake" would have no groove, just lines scored into the jacket.

murf

 

[murf]

tech ninja,

do you own a 9mm sizing die? if so, you can run those cases through it and size the upper portion of the case down a bit more to maybe get you a little more neck tension.

murf

p.s. if you have a 380acp sizing die you may want to try the same thing on those cases. i have never used the 380acp die, but it should size the case more than the 9mm die. just an idea.

 

[Robert101]

Maybe due to the thin plating the cannelure is shallow therefore not a "real" cannelure - which would aid the crimp.