Crunch time for crimps.

[Pond, James Pond]

A puzzling visit to the range.

I took my 18 reloaded .44s and 12 .38s to test the different crimps for bullet retention.

A number of things worried me.

Firstly, that the crimps don't seem to work for the .44 and secondly, that my bullet depth die does not seem consistent and possibly thirdly that my FCD is not up to the job.
How crucial potentially these are, I leave to you lot to say....

I had 5 sets of 6 rounds. 2 in .38 (125gr CU-plated and VV N350) and 3 in .44. (200gr CU-plated and VV N350) The .38s were crimped with 0.5 or 0.75 turns of the Lee FCD. The .44s with 0.5, 0.75 and 1 full turn of the Lee FCD.

I chose one round in each group and measured its OAL. I then remeasured it after each shot of the other rounds in its group. The measurements are in mm.

Here are the sequences of OAL measurements for each calibre and crimp. The first number is before shooting any, the next is after the first shot and so on until the final OAL where the cartridge has endured the recoil of its 5 bed-fellows!

.38 Spl Max OAL in manual: 39.??mm (can't remember off-hand and the paper is in the garage and I can't be bothered to go out now) I can say that the OAL was not massively consistent, despite measuring each cartridge after loading it at the bench: caliper technique?

0.5 turn crimp
39.12, 39.05, 39.04, 39.05, 39.06, 39.06
0.75 turn crimp
39.27, 39.28, 39.28, 39.25, 39.25, 39.26

Here I think the 0.75 crimp is most consistent, but I think the 0.5 could do for my purposes.

.44 Magnum Max OAL 40.70mm
You will see from the first number in each sequence that the bullet seating depth is not very consistent at all, varying by 0.3mm amongst my 3 control cartridges! Is 0.3mm an issue in reloading? I don't know!!

0.5 turn crimp
40.76, 41.05, 41.18, 41.26, 41.32, 41.45
0.75 turn crimp
40.62, 40.89, 40.99, 41.00, 41.18, 41.23
1 full turn crimp
40.93, 41.02, 41.06, 41.10, 41.14, 41.09

So overall, the 0.5 round OAL extended from 40.76 to 41.45 and showed no signs of settling.
For the 0.75 it was 40.62 to 41.23. A lower degree of bullet egress showing signs of stopping.
The full turn round went from 40.93 to 41.09. The smallest increase and had shown signs of leveling off.

What does this tell you apart from the fact that perhaps I can't use calipers porperly?

Are there other more subtle signs relating to powder choices, velocities or bullet type?

To help, there is also a photo attached of a full turn crimped bullet that I used in the die adjustment phase and extracted with a bullet puller, so you can see the degree of deformation to the bullet.
Evident, but not brutal, I think... or is it?

Thoughts?

[Unclenick]

Thanks for sharing an interesting experiment.

I don't see a real problem. 0.01" (0.25 mm) of length variance in bullets isn't unusual, nor is it unusual for COL from one round to the next, even when you aren't pushing a crimp in. Once you do impress a crimp, you elongate the bullet. The length can go toward the tip or the case in varying degree, so it's not at all odd you see the variation that you do.

As to "egress" (SAAMI's glossary refers to this as "bullet creep", "bullet popping", or "bullet starting"), it depends on several factors, including bullet/case friction, how hard you push the bullet, and how light the revolver is. If you don't get enough to jam rotation of the cylinder, you're fine. In terms of ballistics, your longer starting length won't make a lot of difference.

If you want a tighter grip, be aware that as you increase pressure on a roll crimp, you can cause the sides of the case to bulge away slightly from the bullet. The CFCD carbide ring will push it back, but owing to elasticity of the case being greater than the bullet's (or its malleability being less, depending which way you want to look at it), that won't be a 100% return to contact. The one die I know of that constrains the brass from bulging during crimping in the first place is the Redding Profile Crimp die, and that might be another course for you to try taking to reduce bullet creep further.

[Jim Watson]

If that was a smooth sided bullet and you drove the crimp into it that deep, I would call it brutal.
I would be looking for some bullets made with a crimp groove for the purpose and save the smooth ones for light loads that will not move them when lightly crimped.

[Misssissippi Dave]

Look at it this way. .2 mm variance is fairly common when loading on a progressive press. You should be fine.

[jepp2]

You probably already know all this:

- case length variation will cause variations in degree of crimp. So even if you change degree of crimp by adjusting the die, amount of crimp can vary due to case length.

- Which bullet seater plug are you using? If you are seating off the nose of the bullet the variation should be less than if you are seating off the ogive, assuming you are measuring OAL from the bullet nose and not the ogive.

I can say that the OAL was not massively consistent, despite measuring each cartridge after loading it at the bench: caliper technique?

- Did you correct the variation in OAL so the after firing results of remaining loaded rounds are from the same basis?

- How are you expanding you cases? The Lyman M die (or Redding equivalent) will provide excellent bullet alignment and control how much the case is expanded. If you bell the case too much, you will not have the same neck tension on the bullet and the bullet will move more during recoil.

For a plated bullet with no cannelure, I think that is WAY too much crimp. The bullet is significantly deformed, and with a plated bullet you have greatly increased the risk of the jacket separating from the lead core.

[Cary]

Correct me if I'm wrong. Isn't the force necessary to move the bullet from the completed cartridge called "bullet pull"? Isn't the majority of bullet pull attained from neck tension and not crimp? If these ideas are true I am amazed at the number of people who think crimping the living day lights out of a bullet will solve bullet pull problems and improve accuracy. I've seen way too many bullets that look like the posters picture because of the idea that crimping plays a big part in bullet pull. I'm of the opinion that it doesn't and as Unclenick stated it can have the adverse affect if carried too far. I'm off my rant now.
Cary

[mrawesome22]

Originally Posted by Jim Watson

If that was a smooth sided bullet and you drove the crimp into it that deep, I would call it brutal.
I would be looking for some bullets made with a crimp groove for the purpose and save the smooth ones for light loads that will not move them when lightly crimped.

Perfect.

sudo apt-get update

[Pond, James Pond]

OK thanks for the answers and I will try and provide my own to the questions some of you have asked. However, as you know, I'm new to this and so sometimes my initial answer to a tech question is "Wha....?!"

So...

If that was a smooth sided bullet and you drove the crimp into it that deep, I would call it brutal.
I would be looking for some bullets made with a crimp groove for the purpose and save the smooth ones for light loads that will not move them when lightly crimped.

That is a light load. It is the starting load for that bullet weight, as best as I could work out. As I used FMJ load data, I imagine that it is a little more than would be the starting load for CU-plated, but still pretty low.
I don't see myself getting new bullets until these have run out. The source for these bullets and their price is my local range. they will not order more for some time and to order independantly is very expensive. When they next order I can get some cannelured 200gr and 300gr bullets.
One questions jumps to mind when I read your comment: "If that is true, then why does the manufacturer even bother making a .429 bullet without cannelure? It is not like .44 loads are ever going to be weak, and recoil of no consequence...

- Which bullet seater plug are you using?

The bullets are truncated cones, as you see from the picture. I use the plug that came with the Lee die kit: probably a concave one. I imagine it pushes on the ogive. I set my bullet depth by incrementally winding in the seater until the calipers read the desired OAL.

Did you correct the variation in OAL so the after firing results of remaining loaded rounds are from the same basis?

Not sure I understand the question. The measurements are for the exact same cartridge, retrieved from the cylinder after each shot of other cartridges.

How are you expanding you cases?

Lee expander and through loader die.

Bottom line here folks, is that I'm still no wiser on which crimp level to use.

If crimp is only to prevent the bullet coming out too far then I can live with 0.5 as I tend to shoot everything I take to the range and so it will not get the chance to extend to length that threaten to lock the action.

If bullet creep beyond Max stated OAL by 0.75 mm is not a danger for increased case space or pressure spikes, then I can also live with a 0.5 turn crimp.

If "creep" or "pull" is an issue, how much is safe and if not 0.5 turns, then will 0.75 do? If not, and 1 turn is too much, where next?

The view that I'm not doing it properly is coming in loud and clear, folks...and it is justified , but I still need some idea of how to do it right!!

Ideally, I simply want to know which of those respective calibre crimps you would use, given the data.
If none are up to task, then please explain why and how you would rectify the situation.

I'm so close to a working round, I can taste it!!!

[Edward429451]

That did look pretty brutal. A lot of people use too much crimp. That was a full turn? Try a half turn. Or less.

James, I'm thinking that perhaps simple terminology may be giving you trouble here. Try not thinking about "crimping" it, but rather just folding over the case mouth a little. "Crimp" suggests tightness and while it is a technically accurate term it should be viewed with a grain of salt and not overdone.

I'm pretty sure that none of my 44 Mag loads have ever taken more than .5 crimp, many are .25

[bossman]

Hang in there, for the 38 spl and 44 spl try 1/4 turn and 1/2 for the 44 mag side. Your full turn crimp is overkill. I shoot a lot of 38 spl and they really don't need much of a crimp at all. Practice and reloading will soon get your seating depth problems figured out.

[Pond, James Pond]

I'm less worried about the .38 as it seems that the .75 crimp OAL was not changing so much after the first couple of shots.

One note on the .38 side:
I used the Lee die reloading chart as they had the exact grain and type of bullet: 125 gr and plated. However, their OAL was 39.something (39.39mm, I think) and with that the bullet was barely in the case!! About 3 quarters was poking out of the mouth!!

Is this OK?

I'm pretty sure that none of my 44 Mag loads have ever taken more than .5 crimp, many are .25

I see what you're getting at with the terminology. I think my biggest disadvantage, which I touched on in my other crimp conundrum post, is that I have no frame of reference.
Manuals don't provide pictures saying "Fig. A shows a hideous crimp that only an ex-pat in Estonia could manage, whereas Fig. B is perfect!!"

As for your suggestion of .25 turn crimp: my only reservation is that with a half turn crimp, the OAL was clearly getting larger with each shot... The crimp was not holding the bullet steady in the case mouth, and I had understood that this was its purpose in the whole reloading thing...

A quarter turn crimp would surely be even worse.

I'll bow to the greater knowledge of those on here and if you tell me not to worry about that bullet creep, then I'll shrug my shoulders and go with that half turn or less.

However, I just want to do it right.

But if, for example, the bullets I have are not up to .44 Mag performance or the powder unsuited to the bullets, best I know now.... although I won't be best pleased!!

[jim8115]

For what it is worth, I only go 1/4 turn with the FCD on my 38's. 357's anywhere form 3/4 to 1 turn

JIM

[Brian Pfleuger]

Originally Posted by Pond, James Pond

A quarter turn crimp would surely be even worse.

Can't say with certainty but sometimes more crimp creates LESS tension because it bends the rest of the case body out away from the bullet.

[Pond, James Pond]

OK, then!!

Only one way to find out: quarter turn crimp batch coming up after my holidays!!

[buck460XVR]

If you used a FCD with soft plated bullets you could have actually lessened the amount of neck tension by swagging the bullet down. Plated bullets used in revolvers are for light loadings using a taper crimp. These loadings are generally mild enough that "bullet jump" is not a concern. Roll crimping a plated bullet without a cannelure or even over taper crimping them can cause the case to cut thru the thin plating resulting in inaccuracy and/or plating separation. You enclosed picture shows how much your crimp deformed the thin plating and the soft lead core beneath it. This certainly could have contributed to your inconsistent OALs.

[mrawesome22]

Are you still using that powder that reaches 1400fps with the start
load?

If so, you need a different powder. Get velocity down to 1100 fps or so, and you won't even need a crimp. Those bullets you have were not designed for high velocity.

So, again, change powder, or change to a bullet designed for what you are trying to accomplish.
sudo apt-get update

[Pond, James Pond]

If you used a FCD with soft plated bullets you could have actually lessened the amount of neck tension by swagging the bullet down.

Do you recommend foregoing the FCD and opting for the taper crimp in the bullet seater die?

Are you still using that powder that reaches 1400fps with the start
load?

If so, you need a different powder. Get velocity down to 1100 fps or so, and you won't even need a crimp. Those bullets you have were not designed for high velocity.

So, again, change powder, or change to a bullet designed for what you are trying to accomplish.

Yes, I am.
Unfortunately, I don't have $80-90 to buy another half a kilo of another pack of powder. Nor do I have the €100 needed to replace my chosen bullets with something from the only other supplier: Midway Germany, who charge (excuse the pun) an arm and a leg.
Hopefully in a month or two, I'll have some more options. In the meantime, I'll still shoot what I have for now. Better than nothing.

Out of curiosity, where did you get these velocity data? I have not seen any max velocities on the bullet supplier's page, for individual bullet types.

In fact, I have found a reference to using the slowest burning powder possible to reduce to starting velocity, despite the muzzle velocity being higher. In other words, the bullet maker recommend N100 (1600fps) over faster burning N320 (1200fps), because of the starting velocity as the bullet starts to bite the rifling.

In my other crimp post, you recommended staying away from slower burning, whilst the manufacturer promotes them.
Have I misunderstood what they mean or what you wrote?

So now I'm a bit confused.

[mrawesome22]

Q:How fast can I shoot these bullets?

Velocities depend on the caliber, but as a rule of thumb, we recommend you don't shoot our plated bullets over 1250 feet-per-second. Our 44's actually shoot best around 1150 fps. 45's are generally good at 850-900 fps. Our bullets are not recommended for magnum velocities over 1250fps unless the bullet description denotes a thick plated bullet with a higher listed maximum for velocity.

http://www.berrysmfg.com/faq-q10-c1-...e_bullets.aspx

Frequently Ask Questions
Q1. Do you have a minimum order requirement to buy direct from the factory?

A. Yes, 35,000 bullets. You can mix and match anyway you like to get to an order of that size.

Q2. Do I need an FFL to buy direct?

A. No

Q3. Do your bullets have ANY velocity restrictions?

A. In general, our bullets typically perform their best when shot at velocities no greater than 1,200 to 1,250 Feet per second (FPS).

Q4. What type of crimp should I use?

A. A slight taper crimp is what we recommend. Lee Factory Crimp Die.

Q5. Why are there no cannelures on any of your bullets?

A. Because our bullets are so soft a cannelure groove is not needed to achieve a positive, tight grip of the bullet in the case mouth.

Q6. What if I can't find load data for your bullets?

A. If you have a load for a cast lead bullet, that will transfer across the board as far as our bullets go. We recommend a starting powder charge directly between the listed minimum and maximum load.

http://www.rainierballistics.com/faq.php



sudo apt-get update

[Pond, James Pond]

I'm getting my bullets from HNsport.

They don't appear to have gone into the same degree of detail as far as velocities is concerned.

However, they do say that their bullets are "High Speed" so perhaps the warnings to customers on the Berry's website do not apply.

In fact, I found a figure of 450 m/s on their load page.
That is about 1450 ft/s. This should give me a greater margin of comfort.

[Jim Watson]

What is the diameter of your expander plug?
It should be substantially less than bullet diameter for adequate "bullet pull."
A good friction fit is of more value than a hard crimp.

If you could improvise a method for flaring the case mouth just enough to start the bullet in the seater without expanding the case below the flare at all, it would be an interesting experiment.

[Pond, James Pond]

What is the diameter of your expander plug?
It should be substantially less than bullet diameter for adequate "bullet pull."
A good friction fit is of more value than a hard crimp.

No idea on the diameter.

However, the expander die is also the charging die and it is set up in such a way that the bullet's rim, when later placed in the case mouth, only really nestles on the lip to allow it to stay in position for seating.

Effectively, almost no bullet length is in the case, before being seater in the next die, so flaring is quite minimal, I think...

[mikld]

Didn't see it in the above posts, but for plated bullets use a taper crimp. I would think Lee's .44 magnum FCD is roll crimp. FWIW I had a FCD in .44 magnum I used once. Got terrible leading, inaccuracy. Knocked out the carbide ring. Crimp from the die is now "junky" so I tossed it. Went back to using Redding Profile crimp and on lead bullets RCBS roll crimp...

[Clifford L. Hughes]

Pound James Pound:

The crimp on a pistol bullet is to keep the bullet from jumping under recoil. The friction from the case holds the bullet. If you have loose bullets in your fully sized cased check the diameter of your die's expander ball: it may be too large ad require reducing its diameter. In all of my years of reloading I never ran across this.

Semper Fi.
Gunnery Sergeant
Clifford L. Hughes
USMC Retired

[Pond, James Pond]

Well, I made a selection of new crimps.

One was without crimp as a sort of control.
This cartridges OAL was 40.75mm starting OAL, 41.23mm after the first shot and 41.94mm after the second. After this second shot, I scrapped this set and shot the lot: clearly there was no retention and continuing the experiment was fruitless.

The next was 0.25 crimp with OALs as follows:
40.71mm, 40.78mm, 40.89mm, 41.11mm, 41.10mm, 41.18mm.

Compaing these results and the OAL values in my OP, it looks like the 0.25 turn crimp is the most effective although not particularly effective....

It seems that these bullets, with their waxy coating and no cannelure are not ideal, but they are what I have.

Lesson learnt here is once the cartridges are in the cylinder, they don't come out again until they've been fired!! that way I can be sure that the bullet on the 6th shot will only have crept forward by about 0.5mm...

When I get some 300gr bullets this process is going to be interesting!!

[SL1]

Mr. Pond,

In all this, I have not seen a mention of accuracy.

If you start looking at the effects of crimp on the group sizes that you get at some decent range like 25 yards (or meters), then I think you will be able to see where too much crimp is affecting accuracy.

If you can find a load where bullet jump is not a problem with tying-up your cylinder and the accuracy has not deteriorated, then your bullet/powder combination seems workable. But, if your accuracy goes bad before your crimp is strong enough to stop the bullets from pulling out too far during recoil, then you need to work with a stronger bullet (jacketed or hard cast) or a powder that produces a less powerful load.

A decent gun with good ammo should be able to produce about 2" groups at 25 yards if you can (properly) steady our hands on a bench when you shoot. (Don't rest the gun itself on the bench, as that will enlarge groups.)

SL1