help me understand crimping

[44 AMP]

What happens if this doesn't correspond to the stated COL

Ignore the stated COAL. With a revolver your max COAL is the front face of the cylinder, in practical terms.

COAL (Loaded length with bullet) is not a hard and fast rule, its not a law of nature, it is the industry standard max length that SHOULD work in all firearms of that caliber. (not stick out of the cylinder, feed through the magazine, etc.) Also to keep the bullet from touching the rifling when chambered. (not an issue with revolvers, or most pistol rounds, but something to watch for with rifle bullets)

Factory ammo is loaded a bit shorter than max COAL, in order to help ensure it works in everything.

Generally, bullet makers put the crimp groove in a location where the bullet length, when seated to the crimp groove is within max COAL. Generally. Not always.

New 9mm dies should have a taper crimp, not a roll crimp, I don't think anyone has made roll crimp 9mm dies is a long time. But, they used to. You CAN (if you know just what you are doing) use a roll crimp die to remove case mouth flare, and give just a tiny bit of crimp that will not affect chambering to a 9mm or other auto pistol round. HOWEVER, its delicate work, and the taper crimp is much, much more "user friendly" so mere mortals have a much better chance of doing it right with a taper crimp.

Setting your die to roll crimp in the middle of the cannelure is the best choice. As mentioned, as long as the case has somewhere to crimp into, it will be ok.

Again, I will say, uniform case lengths are a must for (batch) production. A couple of thousandths of an inch case length can make the difference between a good crimp, too much crimp, or not enough crimp. (roll crimp) its not nearly as important with a taper crimp, but it still does matter.

ALSO, uniformity of crimp can affect accuracy. One way to ensure uniformity is to measure all your brass, find the shortest one (that you are going to use) and trim the rest of them to that length, then adjust your die for that length case.

Your flared 9mm cases may chamber in your barrel, but might not FEED into your barrel very well, if at all. What I have found works for me in several different guns in both 9mm and .45ACP is not to just remove the flair of the case mouth, but to add just a tiny "kiss" of taper crimp. IN my guns, the little bit of taper crimp seems to improve feeding, the rounds are just marginally "smoother" and that gives me to fewer jams.

I do this by using a factory round, and adjusting the die so the crimp is in firm contact with the case (hand tight), then removing the case and turning the die body down just a tiny bit more. Works for me, what works for you might require a little trial and error, but I think the way I do it is a good place to start.

Good Luck, and we're here to help.

 

[Ocraknife]

Thanks everyone. This has helped immensely.

That said, I really think I've made a mistake in getting into reloading/handloading.

I had no idea that I'd have to be dealing in distances a half the width of a human hair and weights less than a single grain of sand.

I'm not even trying to produce match quality ammo. I'm just trying to make range stuff in a safe range of pressures.

 

[TailGator]

Don't get discouraged. You typically tweak your dies until you get them right, then do little or no adjusting for long periods thereafter - just correct whatever tiny amounts of drift might occur.

You learned a lot on this thread, and the same knowledgeable folks will help out again if you need them. We have all been where you are now, some a year or two ago, and some a few decades ago.

 

[condor bravo]

Piecing together and trying to best utilize all of the posts, one can sense that the whole process at times may seem a little daunting but split hairs and other details become common place and acceptable as you progress and the whole thing suddenly comes together. Just hang in there.

 

[Ocraknife]

Thanks everyone. I really appreciate all your help and insight.

 

[briandg]

The Instructions to measure every round of pistol brass is way off base. This is one of the reasons I said that you should crimp separately. Seat to proper length without setting the crimp. Then, crimp by FEEL. It's not hard to l earn what pressure is needed to create the proper crimp, and just duplicate that

But, the fact remains thT millions of reloads annually are fired with imperfect seating and crimping. Accuracy can't possibly be affected badly enough to be noticeable unless shooting for absolute accuracy. All of the guys who reload on progressives would confirm that absolute perfection in ammo vs accuracy isn't a genuine concern to anyone who does shoot for precision accuracy.

 

[Lost Sheep]

What Tailgator said

Thanks everyone. This has helped immensely.

That said, I really think I've made a mistake in getting into reloading/handloading.

I had no idea that I'd have to be dealing in distances a half the width of a human hair and weights less than a single grain of sand.

I'm not even trying to produce match quality ammo. I'm just trying to make range stuff in a safe range of pressures.

Reloading is not rocket science. It does involve smoke and flame and things that go terribly fast, but if you can follow a recipe to make a cake and change a tire without losing your lug nuts, you can reload safely and accurately.

Everything is logical and reasonable, if sometimes difficult to figure. If you find COAL shorter than the book says, that just means you have a bit less volume inside the cartridge than they did with the ammo they tested. If you are near maximum charge weight, you might was to reduce the charge weight a bit. But you should not be starting near max anyway. The principal is that in a smaller volume, pressure rises faster and higher, all other things being equal.

An apparent anomaly is that heavier bullets require less powder. This seems odd at first until you note that a heavier bullet takes a bit longer to get moving and the powder thus has more time to build up pressure. So less powder is required to get up to the powder's and the gun's operating pressure envelope. Also a heavier bullet is longer and will (if COAL is the same) leave less free volume in the case than a shorter, lighter bullet.

Physics is not magic and the loading manuals have all been thoroughly vetted.

That some manuals do not agree on load recipes is also logical. They use different firearms, primers, etc. and sometimes the labs (even while following SAAMI standards) have slightly different procedures. This is one reason shy many reloaders have a whole bookshelf of manuals to - to cross-check different sources and maybe average then all together.

Lost Sheep

 

[mikld]

Don't overthink nor fear the process. Reloading is broken down into steps, each step in itself can be as simple or complex as you make it. Take each step separately (which is another plus for learning on a single stage press), and K.I.S.S. "The ABCs of Reloading" has photos breaking down the process step by step, with separate sections for rifle and handgun reloading along with clear written instructions. Give it a look

Crimping is one step that can be confusing, but simply, crimping is forming the case mouth, to either add "holding power" for the bullet or smoothing the case for reliable chambering (semi-auto ammo). One way to crimp revolver ammo is have a factory round on hand and copy the appearence as to where and how much to crimp. Iff you crimp too much you will see the results immediately; crushed, bulged cases or deformed bullets. Or too little; chambering difficulties (both revolvers and semi-autos), and "loose" bullets.

Measuring gunpowder charges can be scary (I was "apprehensive" the first 100 or so rounds), but paying attention to the step is easy and +/- a couple tenths of a grain (kinda small, but doable) variation is still safe when you are following your reloading manual's starting loads.

Some mechanical ability is needed but less than fixing a leaky toilet, and much like using a cookbook (just following directions). The rewards are worth the effort and the shooting of your own hand made ammo is very, very satisfying. Give it a second thought before throwing in the towel...

Go slow, double check everything, and most important, have fun...

 

[jetinteriorguy]

I'll make your life simple for the .41, get the Collet Crimp die from Lee. Much less finicky with brass length for less trimming, and much easier on the brass for extended brass life. I shoot heavy loads in both my M57 and my Henry big boy and have experience absolutely no setback. They don't list it for the .41 on the website but you can get them by special request. I've been using mine for both .357 and .41 and consider it the best thing for crimping ever. I'm lucky with my 9mm, my Lee FCD is slightly oversized so it works well to taper crimp.

 

[44 AMP]

The Instructions to measure every round of pistol brass is way off base. This is one of the reasons I said that you should crimp separately.
Seat to proper length without setting the crimp. Then, crimp by FEEL. It's not hard to l earn what pressure is needed to create the proper crimp, and just duplicate that

I don't think measuring your brass is way off base. Not when it comes to setting your dies. Let's take the .41Mag for example, max case length is 1.290", trim to length is 1.285". And while most fired brass with be pretty close to each other in length, there will be cases shorter than average, and cases longer. Sometimes only by a little, sometimes not. If you don't measure, (in some way, even an eyeball comparison is measuring, though not very precise) then you simply won't know.

Say you've got a few cases that only go 1.280" If the case you use to set your die for the right amount of crimp is 1.290", then the short case doesn't get the right amount of crimp. IF you happen to use a short case to set your die, then the long one doesn't get the right amount of crimp (in this case, too much).

Maybe it makes a significant difference, maybe it doesn't for what you are shooting, and what you are shooting it in. Lots and lots of factors involved in how important it is to you, or to me. One way to avoid this complication is to measure, and trim to a uniform length.

I have nothing against crimping as a separate step, and using a separate die to do it. And yes, I do work by feel to a degree. Once you have things set (properly adjusted for what you want), you get a feel for the amount of force it takes, when things are right, and so you can tell by feel when things aren't.

At that point, you can stop and adjust again (by trial and error) for that individual round. A separate crimp die means when you do this, all you are adjusting is the crimp, and returning the die to its original setting is simpler.

If you are willing to adjust your die(s) for each individual round, you certainly can. (you won't have to adjust for every single round, but you might have to adjust for ANY individual round, and then back for the next one) I do it when loading small numbers of rounds, using brass that hasn't been "uniformed" for length.

Handgun rounds are generally more forgiving of crimp errors than rifle rounds. A little too much crimp might not make a noticeable difference in a revolver round, yet the same amount of being "off" in your crimp in a .30-30 might result in a bulged shoulder and an unchamberable round.

the fact remains thT millions of reloads annually are fired with imperfect seating and crimping.

Oh, I agree, absolutely. Some of them are even mine! People shoot everything from perfect ammo to absolute crap. For a lot of things, it doesn't have to be perfect, it just has to be good enough. Some of us shoot them if they're only going to be good enough, once.

Can't tell you the number of times I've had a well used case get a crack in the mouth when being flared. When this happens, I still load the round and shoot it. One last time. (not with any high end load, though, I'm cheap, and foolish, but I'm not an idiot ).

(or, at least, I don't think I'm an idiot. )

 

[Sevens]

A big "+1" to briandg's post. Folks are way (way!) overstating the importance of case trim length for handgun brass.

There are some times when it certainly helps to trim heavy magnum revolver brass... but for the most part, trimming pistol brass is wasted effort that you'll simply never notice.

14,600 loaded last year... nearly 9k loaded so far in 2016... I've still never once trimmed a piece of handgun brass in my life. And some of my handguns/ammo slap 100-300 yard steel on the rifle range.

 

[Ocraknife]

I took a picture of some premium factory .41 ammo that I have to show the crimp it has. Is this an example of a proper roll crimp?

[/URL]

 

[condor bravo]

Looks close enough to be proper I would think but from the photo can't really tell how deep the case rim is crimped into the cannelure (possibly not enough) or how well the crimp is centered. The magnified image probably just makes it a little distorted.

 

[briandg]

Ocra, the purpose of the crimp is to hold that bullet tightly in place while handling and to a certain extent hold it in place long enough to allow the powder charge to become fully ignited. If you look at your photo you will see that the mouth of the case is pressed inward in a tight ring. That is a good, solid crimp for a magnum pistol.

 

[Pond James Pond]

I took a picture of some premium factory .41 ammo that I have to show the crimp it has. Is this an example of a proper roll crimp?

Looks about a thousand times better than my first attempt at crimping.

(Please don't do a search.... )

One piece of advice that I received and have not seen given here was simply this:

Once you've established if you need roll or taper, then take a factory load of the same calibre and try to emulate the crimp they have used as a guide.

To my mind that is what you've done.

 

[briandg]

I keep saying, like a broken record, you absolutely need a good pair of reading glasses to give you enough magnification to see details like your crimp or primers and you should have an even stronger magnifier of some s of Dr, ten power or more, and I have a forty power loupe.

You won't need this all the time but you can use it to learn details as you just showed us, you can even use you digital camera and magnify the image.

 

[44 AMP]

I've also read that all revolver rounds need to be crimped but I don't know if this is true or not

It's not true. ALL revolver rounds do not need to be crimped. But none of them suffers from a proper crimp, so they all get crimped as factory ammo.

The main purpose of the roll crimp on a revolver round is to help prevent the bullet from moving forward during recoil. During recoil, the inertia of the bullets in a revolver cylinder acts like a bullet puller. The gun, literally, recoils away from the bullet.

HOW much effect this has depends on many things. Size (weight) of the bullet, amount of recoil (including not just the powder charge, but also case neck tension, the weight of the gun, and possibly even how it is held), and amount of crimp all factor together.

How much crimp do you need???
The answer is...it depends..

It depends on what you are shooting, and what you are shooting it in.

You can shoot uncrimped .38 Spl target loads out a heavy frame revolver all day and I doubt you would see any bullet creep. Out of a light pocket gun, it can be a different story. A heavier recoiling load out of the heavy gun can be a different story as well. Larger calibers amplify the effect.

Run your own test, it only takes a few rounds. Load one with no crimp. Then fire the other rounds in the cylinder, and look at the uncrimped round. If the bullet has moved, you need some crimp.

Repeat with increasing amounts of crimp until the bullet doesn't move. You're there, for THAT gun with THAT load. Add just a little more crimp for "insurance" and you're good to go.

This process will show you the minimum you need for your combination of load and gun. I did my own test ages ago for my .45Colt Ruger Blackhawk. In that gun, the way I shoot it, using standard factory level loads (250gr bullet), I found that there was some bullet creep on the last round in the cylinder. So for that gun, with those loads I needed at least a little bit of crimp. Because I normally shoot heavier than the original factory loads, I use a heavier crimp, and have no issues with bullet creep in that gun.

I can also shoot the heaviest (safe) loads from my Contender with NO CRIMP, and NO ISSUES. Because it's a single shot.

The gun does matter.

 

[briandg]

A caveat to that . You have got to crimp down the belling/flaring created during expanding. If you don't, you will wind up with a tiny ring of brass locked into the cylinder wall so hard that you night even have to hammer each round out with a cleaning rod.

This should also be a reminder that a person shouldn't experiment t without putting a lot of thought to it, and maybe asking here to see if that test has already been tried.

A whole lot of people died during nuclear experiments, and really, you'd think that those guys would have been careful...

 

[mikld]

If all your crimps look like the pic. you're doing pretty good. Pesronally, and of course it's just my experience, I go a hair deeper with the bullet and for my magnums a bit more "roll". But that's for me and my magnum ammo, the pic is a proper roll crimp.

For all intents and purposes, and especially for a new reloader, all revolver rounds should be crimped, K.I.S.S.! After you gain experience, then you can try different crimping/no crimping, but for now just stay with the basics...

A lot of reloaders on forums tend to over explain answers to new reloaders' questions. Most are correct, but often get into the "advanced reloading theory" areas. I emphasize K.I.S.S. as the beginner's attitude because it's very easy to make a simple process very complex and often confusing.

 

[44 AMP]

you will wind up with a tiny ring of brass locked into the cylinder wall

I've never seen that, but I won't say you are wrong. I don't believe I've ever shot any ammo that did NOT have the belling/flare "straightened out. My seating dies take care of that, well enough, and since I have them adjusted to crimp during seating (some calibers) or run the rounds through a separate crimp die, to give them all at least a tiny "kiss" of crimp, I've never noticed the problem you describe.

I have seen the crimp shoulder in a die cut a ring of brass from the case while crimping. Don't much care for that, myself. Fortunately, it doesn't seem to be a common thing.

A whole lot of people died during nuclear experiments,

Not that I am aware of, unless one defines "during nuclear experiments" differently than I do. If one defines Hiroshima and Nagasaki as "nuclear experiments" then I would have to agree. Otherwise I don't believe anyone has died during a nuclear experiment, not in the US, at least.

During the years when radiation and nuclear materials were less well understood, several people did receive fatal exposures, due to accidents during experiments, resulting in death, days, weeks, or months later.

And a handful of people have been killed during nuclear accidents in "the industry". Many times many more people have been killed in industrial (non nuclear) accidents at nuclear sites over the years.