Can You Over-Crimp A Revolver Load?

[Nevada Ed]

A little crimp on my 357 case goes a long ways.

I set my die to a taper crimp and a "touch" more for my light
lead practice loads whit the screw pin sticking 1.27" above my
locking screw on the die.

For a medium crimp on lead or all my Jacketed bullets the pin
is set to 1.265"

My heavy lead setting is set at just 1.26" above the locking screw.

As you can see, with my dies, a little goes a long ways......
and yes the heavy crimp on the deep LSWC cannelure can be
a bummer, if you need to pull this style bullet.

I have broken one inertia bullet puller.
From now on I usually just shoot the mistake or bad round unless you can't live with it.

 

[len917]

After I started using the Lee Factory Crimp die I have not had a bad crimp. I don't know if it is possible to get a bad crimp with it.

I also use the Factory Crimp Die from Lee. You can over crimp.
Feel the cartridge to see if there is a bulge where the case and bullet meet or drop it in the cylinder. As far as not enough crimp, feel that area with your finger, if you feel too much case edge, tighten down 1/16 turn at a time until it feels right which would be a very, very slight feel of the case edge.

 

[GypsmJim]

Thanks for all the comments. Sounds like I'm OK. I did have an issue with a box of 45 Colts last Summer, where the bullets were jumping the crimp in a revolver. The crimps on those "looked" OK, so I was a little concerned when I reloaded the batch this week.

The cases I loaded were purchased in 1972, and the box has been reloaded so many times that the tag inside the cover had no more space for marking reload numbers, so I guess I haven't damaged a case yet by crimping too hard.

Thanks again.

 

[forestswin]

Thanks for all the comments. Sounds like I'm OK. I did have an issue with a box of 45 Colts last Summer, where the bullets were jumping the crimp in a revolver. The crimps on those "looked" OK, so I was a little concerned when I reloaded the batch this week.

The cases I loaded were purchased in 1972, and the box has been reloaded so many times that the tag inside the cover had no more space for marking reload numbers, so I guess I haven't damaged a case yet by crimping too hard.

Thanks again.

I'm not too sure if you're okay
How many times have reloaded the cases you are about to reload?

Cases become brittle and stronger from work hardening
(Bending back and forth)
I'm surprised you don't have a bunch of split brass
Eventually, after you crimp a brittle case, it'll bounce back and you'd basically have an uncrimped round.

Its something to check into

 

[Nemo288]

The last frustrating problem I have to overcome is...How to eliminate the bulge that the bullets put in the reloaded cases. It doesn't hurt anything, but looks tacky.

That is the look of a properly prepared round.
Since the bullet is an interference press fit the brass HAS to bulge as it is now bigger than it started if you have sized correctly.
You want the brass to be at least .002" smaller than the bullet in diameter so you have a .001" radial press fit.
The Lee factory revolver crimp dies have a carbide ring that may resize the round back down a little especially if you have loaded an oversize bullet.
Some of us don't want that as we are loading for oversized chamber throats.
Those rounds really have that bulge.
It also helps center the cartridge in the chamber.
You can minimize that look by sizing only the portion that contacts the bullet.
See the thread on neck sizing.

I use the minimum crimp needed for a particular round.
Lower recoiling rounds using faster powders may not need much of one at all if proper bullet pull is achieved thru the process above.
Some times I will crimp just enough to get rid of the bell mouth as described above in the Venturino article.
Ball powder + magnum primer is where the "heavy" crimp comes in.
A magnum primer may, all by itself, have enough energy to start the bullet moving before the powder gets burning completely.
A good crimp helps with this.
Since I have just about given up on ball powder my need for heavy crimps is just about gone.

I use a "medium" crimp on rounds for lever and double rifles.
This is a Redding profile crimp roughly half way into the cannelure of bullets that have one.
For bullets that don't or when the crimp groove does not line up with the case mouth a Lee FC that slightly indents the bullet is used.

 

[Nemo288]

The cases I loaded were purchased in 1972, and the box has been reloaded so many times that the tag inside the cover had no more space for marking reload numbers, so I guess I haven't damaged a case yet by crimping too hard.

As Forestswin mentions, it sounds like your brass is now brittle.
If you want to keep using those and the necks have not split yet, you will be wanting to anneal those case mouths.
I finally learned how to do this after cutting off the necks of rifle brass to make early 445 brass.
The new "necks" were the former bodies and very hard.

Deprime the cases then:
Buy some 450F Tempilaq and paint a little line of it around the middle of the case.
Find a socket driver that the cases fit in loosely but tight enough so they will rotate but you can drop them out by tipping the driver down.
If the case bounces around too much make a cup out of aluminum foil to stick down into the driver.
After the Temilaq has dried fire up a blow torch and sit it on its base near a sink or bucket full of water.
Insert a case into the driver and start rotating it on the slowest setting.
Put just the neck of the case in the flame while watching the temperature indicator.
Just as it starts to melt tip the case into the water.
You are all done except for washing off the now melted Tempilaq.
Acetone worked for me.
Once you get started, it is easier than it sounds. Almost addictive.

BTW this is the Hornady method and I found it much easier than trying to look at 700 or 750F Tempilaq on the necks thru the flame.
Very hard to see accurately.
I used the same (Hornady) driver to paint on the Tempilaq.
Just rotate the case while holding the brush to it.
Unfortunately Hornady no longer sells their kit which was just the case holder/drivers and the Tempilaq fluid.
This method is much simpler and cheaper than the machines they sell and way more effective
than the bake or torch and tip over into the pan full of water method.

 

[rwsmith]

You COULD try this.......

My problem was that about 20% of my reloads would not chamber in my revolver. I thought perhaps a bulged case. I ran them through my Lee FCD, which reduced the percentage, but did not totally solve the problem. Probably user error.

I then had a conversation with an RCBS tech, who was rather snotty...unusual for an RCBS tech, from past experience, but he said that factory crimps are an "overcrimp", and that with RCBS dies, 1/8-1/4 turn beyond contact with the case mouth was all the crimp I needed. Be that as it may, I also use the "fingernail test", as the last poster said.
Since adjusting my seat-crimp die, I've had no need to resort to the FCD.

OTOH, I have started using my Dillon crimp die more since I found out that they both taper and roll crimp. With plated, no cannelure bullets, I crimp just so the flare on the case is eliminated, and moved against the bullet, so there is no "lip" to cause a hang-up. I lightly chamfer the interior of the case mouth, and have seen no damage to the plating when I have pulled the bullets.

The last frustrating problem I have to overcome is...How to eliminate the bulge that the bullets put in the reloaded cases. It doesn't hurt anything, but looks tacky!

I know you can partially size rifle cases with a FL die by having the die raised so that it doesn't contact the shellholder.

I wonder if you could do the same with pistol cartridge cases? I give my cases the full resize treatment because I don't want them to fail to plunk. But you could size cases partially and keep sizing down until you get a good plunk without full sizing. If you have guns, calibers or cases that bulge cases I doubt that this would work.

 

[patrickd]

Yes . Too much crimp will usually cause the case to bulge below the crimp, the bulge can interfere with cambering the round.
Backing off the crimp die will apply less crimp and eliminate the bulge .
Gary

And when this happens you lose all case neck tension. Case neck tension is just as or even more important than a crimp.

 

[LoboGunLeather]

Sometimes it can help to go back to the basics so that all aspects of an issue can be properly understood.

Crimping fixed ammunition serves two basic functions:

1. Secures the bullet in its correct position as seated into the cartridge case. This reduces the possibilities of the bullet 'backing out' of the case, may which can occur with repeating firearms due to recoil of other rounds being fired, or the bullet being pushed deeper into the cartridge case, which can occur with some types of firearms (notably those with tubular magazines).

2. Applies neck tensioning to the bullet, which can provide more uniform and predictable pressures upon discharge, thus potentially affecting both safe performance of the resulting loads as well as accuracy.

Crimping needs vary considerably. A single-shot firearm may have no need of a crimp at all. A tubular magazine rifle may require a strong crimp, particularly those chambered for high-recoil cartridges. A semi-auto firearm may require a strong crimp to maintain cartridges through battering forces of feeding and chambering.

In revolvers of moderate to heavy recoil the primary considerations are:

A. Preventing bullets from 'backing out' due to recoil of other rounds being fired, potentially enough to protrude from the front of the cylinder and disabling the revolver.

B. Providing consistent neck tensioning forces to permit optimal performance of the propellant powder charge. Large charges of slow-burning powders can be particularly susceptible to wide variations in pressure curves due to inconsistent 'bullet pull' forces; very low bullet pull may result in partial or complete failure of the powder charge to ignite and burn, while very heavy bullet pull may result in undesirably high spikes in pressures during the combustion and discharge cycle.

Terms such as 'light', 'moderate', or 'heavy' crimp are largely meaningless due to differences in individual interpretations, as well as differences in manufacturing tolerances (cases, bullets, firearms chambers and bores, etc).

As with each aspect of developing a cartridge load the type and force of crimp needs to be worked into the overall process to determine what works correctly for that application, then consistently applied throughout the loading processes. Enough is enough, and any more may be too much.

 

[SuperMan]

From what the OP is describing he isn't overcrimping just because the bullet was hard to extract.

I have always used a pretty heavy roll crimp {revolvers} regardless if it is a target load of full magnum, fast burning or slow burning powder. Have found that shot to shot consistency over a chronograph much better than with a light crimp.

Also a lot of reloaders have complained about dirty or unburned powder, especially with some of the older powders like Unique and 2400. I've had none of those problems.

As to breaking the plating of plated bullets...I load tons of Berry's .41 bullets and crimp the load hard enough to groove an ungrooved bullet. I've had to pull a few and none of them broke through the plating.

As to case longevity some of my brass has been in use since the 197s and 80s...I get far more body splits than neck splits that ends a case's life...

Bob

 

[Wise_A]

I know you can partially size rifle cases with a FL die by having the die raised so that it doesn't contact the shellholder.

I wonder if you could do the same with pistol cartridge cases? I give my cases the full resize treatment because I don't want them to fail to plunk. But you could size cases partially and keep sizing down until you get a good plunk without full sizing. If you have guns, calibers or cases that bulge cases I doubt that this would work.

You can, but there's no point. All of the stress and hardening on the case occurs at the mouth anyway, from expansion and crimping.

There is a line of thought that by resizing revolver brass as little as possible, the brass is fireformed to your revolver's chamber. But this obviously revolves around (heh-heh) marking and using the same chamber, and most people are dubious of it anyway.