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When I load 38sp's for my S&W 686 revolver, I use a "taper crimp" to complete the load. It was suggested to me that I use a roll crimp instead, when loading for revolvers. Although, I should use the taper crimp when loading for semi autos. Could someone please explain the crimping techniques for various calibers, and for gun types. I have been getting a char burn down the side of my spent 38sp brass, and it seems to be on the lighter side of power.
Haka

Bullets with the cantalure grove are design for a roll crimp and most lead cast bullets. Most all of your std dies are setup for this on those calibers that require it. The 38 Spl and 357 mag need a pretty heavy crimp. This will hold the bullet tight and make the pressures build up higher needed for the powder to burn cleaner. Now some prefer to the the crimp as a seperate step so they can control the bullet seating depth better.

On the bullet seating die, once you have your depth set you normally go another 1/2 turn w/ the die body. You will need to look at the instruction that came with your die set. When doing so you also seat the bullet a little deeper too. So you will need to back it off a tad.

There are even some 9mm bullets out now that require the roll crimp. My carry ammo has it.

Now doing a taper crimp instead of a roll crimp may cause the bullet to be loose.

I think most revolver ammo uses a roll crimp and some rifle ammo.

If your shooting puff loads in a .38spl you may not notice the difference in the crimp much. Start shooting .38+p and .357's and there's a world of difference. A good roll crimp is a must in magnum calibers. IMHO it's almost impossible to get a good roll crimp and seat a bullet at the same station at the same time.

The lip of the case needs to roll over into the cannelure too get a good seal. You will wind up with a lot of unburnt power and under powered loads if not done right.

On straight walled pistol cases it's a little different. We bell the mouth of the case a little to help in setting the bullet. At the crimp station all we are doing is taking the bell back out of the case. Over crimping at this stage usually will just loosen the bullet up in the case.

Hope this helps....

I've done my .45 colt, .38 spec and .357 with, I think, a fairly good roll crimp from the seating die and haven't had a problem. I use the factory crimp die on .45 ACP. I do not use the factory crimp die on 9mm. None are "oh, wow" loads and I seem to get away with it.

Thank you for your responses. I enjoy light to medium loaded rounds, and I have been taper crimping my 38's.
Maybe I need to roll crimp my 38's. I will ask this question, can a good solid roll crimp generate the pressure I need?
I have been using Win AutoComp (6.4gr)on a Berry's 125g plated flat nose, 1.440". According to Hodgdon's Reloading Data Center,
6.4gr of AutoComp is a +p load. They way this load shoots for me is like a 2 on a scale of 1-10 ??? I am thinking of bumping up the load, but that scares me.
Dare to make a suggestion?
thanks, Haka

The bullet seating die does the roll crimp. I wouldn't taper crimp the bullets.

I've never used AutoComp but the load you've given is listed as Max load. I don't go over listed max loads, but I tend to load just this side of pitty-pat. Most of the +P loads I've seen don't give that much of an energy (velocity) improvement over the non +P loads, so I don't load much +P. I prefer to load .357 if I want a bit more punch in the round.

A good solid roll crimp is needed with a lot of powders along with Mag Primers to get a complete burn. A taper crimp may work on mouse load but as you move up the scale you should use the taper crimp. Some do not require a mag primer for a complete burn but some do. I have shot 38 spl at +P loads and they do not come close to matching a std 357mag round so I only load std loads for 38spl but at the upper end of the scale. I'm one also that does not go over published data and very seldom run max loads. I always stay 0.1gr under unless I'm weighing every load. I only have 1 cal that I load max on, rifle round.

If you start using the taper crimp back off you load for pressures will be running higher and look for signs of over pressures at the primer.

Interesting, I've gone to the LEE taper crimp as a separate step for my 357, and it seems to be working as far as accuracy and bullet retention. Rounds that I've taken apart have required massive pressure using my inertia tool. Perhaps I'll have to take a look at my method. I'm shooting all of my 357 loads(cast/Unique) in a Marlin 1894. Regards

I'm using the Lee die as a separate crimp after bullet seating, 4 dies instead of three. They work fine for .38's in my 1894 and my 50th Anny Blackhawk

Something I have just thought of, I loaded some 158gr lswbb 38sp's with 5.1g of Win AutoComp.
These shot well, just as I wanted them to. Same crimp, powder, primers.
When I compare the two loads, it wouldn't seem to be logical (see loads below).
The only difference is the type of bullets used, and the appropriate amount
of powder to correspond. I am wondering if "plated bullets" need more powder because,
in a sense, the plating acts like a lubricant ??? I'm going to have to call Hogdon and see what they have to say.
====================
Berry's 125gr Plated Flat Point, 6.4g Win AutoComp (5.8 - 6.3 gr), 1.440"(shoots wimpy)

Penn 158gr LSWCBB, 5.1gr Win AutoComp (4.8 - 5.3 gr), 1.455" (shoots crisply)

Recoil is the equal and opposite force generated by firing the cartridge. At close velocities the heavier bullet will have more recoil. At max recommended loads the 125gr bullets are at ~1070 fps with AutoComp and the 158gr bullets are ~968 fps. The 158 gr bullets will have ~16% more momentum and ~7% more kinetic energy than the 125gr bullets.

I believe the reason that plated bullets need more powder is that they don't fill and seal the bore quite as well as lead. Lead bullets develop higher pressures.

Thanks Greener,
good info !
Haka

I have used plated bullets for the past 4+yrs due to the fact I shoot in a indoor range and air quality is a requirement. (NO Exposed Lead bases).

The topic of loads on plated bullets has been discussed in length on another forum that I run on. Here is what was found out.

Plated bullets are normally loaded using lead charging data. But not all plated bullets are equal though. Berry's uses a softer plating than Rainer and is slightly thicker than Rainer too. I have noticed over the years that Berry's sizing is more like Lead Cast Bullets so they run about 0.001" larger in dia than Rainers. I have miced them and normally they are 0.0005"-0.001" larger dia on their DS bullets over Rainers. The Rainers at times to seam to under size just a tad to what they post the size to be and a few have not been perfectly round. This can cause a sealing problem to barrel. Berry's say's that you can load from lead loads up to med charge std loads. I think this statement is in the FAQ. Rainer on the other hand do not. For me the Berry's shoot better in my guns. I don't know if it's the over size bullet (getting close to what lead should be) and/or the softer lead used. But in any case if your using Berry's you can go up in change because their bullets fall in between lead and std jacket bullets. Some of the reloads on the other forum push Rainers like Berry's. In both cases
if you load to hot you will strip the jacket off and accuracy will go to shotgun pattern. With the Rainers bullets and there harder cast I find it easier to cut the plating if you over crimp.


Now how does this relate to crimp. The crimp is what holds the bullet in place to prevent setback (or forward) movement during recoil. As you all know setback can also spike the pressures real quick with some powders. It also helps the round to build up pressure and velocity. In most all pistol ammo some type of crimp is used. The Roll Crimp is mainly on Revolver calibers where tapper on auto. If you can push the bullet down with your thumb the crimp is not good.

For a test with the taper crimp on the 38 spl, measure your OAL and confirm they are the same. Now fire all but one then measure the last round. If it has not moved any your getting a good crimp with the taper die. Now if this is a 357 mag that your shooting 38spls through. Shoot the mag rounds with the last being the 38spl, then check the OAL. My guess is the taper crimp will not hold it tight enough.

Is you OAL longer than recommended for your load data? If so your lowering the pressure by the longer lenght.

Much better description and I stand corrected on plated bullets. I meant jacketed, which do carry higher suggested loads than lead.

Good primer on loads, length and crimping.

I've stuck with the lee seating die roll crimp for .38 spc, .357 and .45 colt. I use the separate factory crimp (taper) die for .45 ACP. I've not used the taper crimp on any of my 9mm loads and have had no problems.

Would it be a true statement to say that a 125gr bullet will never get the same recoil as a 158gr bullet if both are loaded to, say, mid load? Maybe I am misinterpreting how the 125gr bullet/load should feel upon firing?