I am confused about how much to crimp my 38 special cases using 158 grain lead semi wad cutter bullets. The SAAMI charts of the specs do not address this question. Since I flare the cases just enough to start the bullet, do I use the crimping die to just close or "tighten the flared area till it just fits nicely in my revolver cylinder or do I want to actually roll it inward some? I wrinkled half a box of rounds by having the crimping die adjusted too low. Any advice is appreciated.
thanks
John

Just slightly roll the crimp so the case mouth slightly curls into the crimping groove of the bullet. This will prevent the unfired bullets from "walking" out of their case during recoil. It will jam up your revolver if the bullet protrudes out of the front of the cylinder. It also helps to achieve proper and uniform pressures from round to round.

I seat all the bullets first and then adjust the die (back off seating portion, bring down crimp portion of die) to only perform the crimp on the second pass. Time consuming, yes, but I only load around 2 boxes at a time. If adjusted properly, very little pressure on the press handle is required to roll the crimp. Hope this helps.

Bigmoose has it exactly right.

There are three types of "crimp" for the 38 case.

Some that shoot low target loads with minimal recoil just
take out the belling which gives a light snug fit to the lead bullet.

Medium loads use the above crimp where the case has a slight
inward roll into the bullets grove. This crimp also works great
on copper jacket bullets.

On high vel or +P lead bullet loads I lower the die 1/2 turn more
and do a crimp that can be easy to see, to work with the high recoil of these loads.

Yow will have to find where "Your die" works with these styles of crimp to get your
loads where you want them.

I also log the height of the die & screw for the bullet being used
and add it to my notes for future loadings.

Good loading.

I use a nice medium crimp for reasons listed above. For high velocity, I step up to .357 mag.

WILDPIG

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I ain't from around here.

You can test the effectiveness of the crimp.

Measure the Cartridge OverAll Length (COAL) of each of six rounds. Mark them somehow (sharpie) or just remember where you load them in your cylinder.

Load your revolver with six rounds.

Fire ONE of the cartridges.

Open the cylinder and measure the COAL of the remaining five cartridges. If the COAL has changed, they're not crimped hard enough. If the COAL is the same as before firing, the crimp is sufficient (or maybe too hard).

Basically you're causing the recoil to try and move the unfired bullets within their cases. If they don't move, the crimp is keeping the bullet in place.

I use a Lee combination crimp+bullet seating die with plated 158gr 38s over midrange target loadings (not too hot, not too mild). The Lee die (not the factory crimp die) does a "modified taper crimp". Or maybe they call it a "modified roll crimp". It's a taper at it's lightest settings. As you crank down the crimp die it becomes a roll. In my settings it's about one wrench flat down from when it makes contact. Sometimes just a tad more. Visually inspecting the finished round, you cannot see any roll.

Just to experiment, I have cranked the crimp die down far enough to crumple the brass case wall. It's not a lot further, maybe another 2 wrench flats past where I consider it "enough".


Sgt Lumpy

Simple illustration of a roll crimp. Image at far right shows a roll crimp into a crimp groove. IMO, the center drawing is too much taper crimp, and the left is what I use for all my semi-auto ammo...

If in doubt about the amount of crimp, look at a factory crimped round (not to be confused with a Factory Crimp Die)

Attached Images

Crimp.jpg (29.1 KB, 645 views)

I use a Lee factory crimp die on almost all of my reloading. It is easy to use and a no brainer.

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Tom
NRA Pistol Inst

Think that my problem was not having the bullet seated to where the rim could be roll crimped into the groove. Instead, I was crimping into the side of the lead bullet very, very close to the actual grove.

Now to really straighten me out, when seating the bullet, do you seat until the brass is level with the top of the groove and then crimp into the groove or do you seat to maybe where the top of the brass is level with the center of the groove and then crimp?

Another thing that I found was that my brass was of different lengths, all within the maximum length. To be able to set my die for all, I plan on trimming all brass to the same length. I was going for a constant OAL. Big mistake. Duh.
Thanks
John

Yes, level with the top of the groove. When the crimp rolls in, it will be right in the groove.

"in the groove"

To get a good visual, pull a factory made round and notice the crimp on their bullet.

The majority of my .38 Specials are for target practice so I go with a very light crimp.

What he said. I load lead wadcutters and semi-wadcutters, and I like a pretty firm roll crimp.

As a note, now that I have a chrony I can tune my loads to "Near" a Fac Dup or "what ever"......
but for "Best Accuracy" I some times have to adjust the amount of crimp on the bullet to get it just right.

A light crimp or a heavy crimp can call for a different amount of powder to stay in the fps area that I am looking for. A lot also depends on the powder you are using.

One reason I am SO HAPPY when I finally find a good accurate load!!

Best of luck.

If you are wrinkling things, get a redding profile crimper. It merges the best of taper and roll crimps into one setup. I use them on all my revolver rounds.

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SWCA 1646

For 38 I use a slight crimp. You need a lot less than you actually think. Even my 357's I don't use a heavy crimp. ImageUploadedByTapatalk1386729322.204679.jpg

SO one above mentioned a crimp thats to heavy. What are the symptoms that you are crimping too hard? I don't mean crumbled brass. what other issues are apparent?

For medium revolvers with .38, just a light crimp is needed. Perhaps in a J frame or alloy revolver a little more crimp would be needed.

If you dig into the side of the bullet or change its shape, that is too much crimp.

For cast bullet "target" loads, I've had the best accuracy from minimum loads of fast powder - & a very light (0.002" - 0.003") crimp. Trimmed brass. Some .38spl match shooters, recommend a 0.000" crimp.

That said, I've found that some what heavier powder charges, seem to do better accuracy wise - w/ a slightly heavier crimp.

As long as the bullets are not un-seating from recoil (doubtful w/ target velocity loads), a good rule of thumb, is no more crimp then is required for best accuracy.

I like the idea of the Redding Profile die, used in a separate step.

I use Dillon .38 / .357 dies, & have 2 sets - each w/ it's own different crimp profile. Dillon tells me that the old style is close to what would be considered a classic "taper" crimp, where as the newer is closer to a "roll" crimp.

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Regards - GCF

How is it possible to measure the size of your crimps?.002-.003 or 000 how do you size that? sorry if its a lame question , but I am not a machinist and learn the hard way.

I get new brass by buying factory loads and I just copy the factory crimps.I'm pretty sure those guys know what they are doing.

Not a lame question.

Assuming here, that seating & crimping are done in two separate operations. Back your crimp die off, until it does not contact the case neck.

After seating a bullet - but before crimping, measure w/ a dial caliper, the outside diameter of the cartridge about 1/4" back from the top edge of the neck.

Now, measure the neck (the area that would be crimped) OD. Before crimping, both OD measurements should be the same (0.000" / zero crimp) - as the seater die removes the bell, but does not crimp unless adjusted to do so.

Adjust the crimp die down, until it just touches. Then slowly (1/8 - 1/4 turn at a time) adjust the crimp die down, & measure VERY CAREFULLY measure edge of the crimped case neck w/ the dial calipers - after each turn.

It's tricky, but not rocket science. Good light & good eyes help.

The measurements on my .357 / 158LSWC / WW231 (3.4 grain) target loads, are 0.377" / 0.372" (crimp), giving me a 0.005" crimp. I might be able to get away w/ less.

Taking that a step further, I call it my baseline crimp - & mark the die. For a heavier load (or slower powder), I can adjust down 1/4, 1/3, or 1/2 turn more as needed - without worrying about taking further measurements.

The actual measurement isn't even essential - as long as you establish your baseline. No crimp, barely crimped, medium crimp, heavy crimp, & pinched that baby plumb off crimp. Heck, you get the idea...

Bear in mind, that "baseline" will change - w/ different bullets.

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Regards - GCF

Very little roll crimp is needed for the .38 Special, if at all. It doesn't have the recoil of the magnums and is less likely to suffer bullet jump.

I just ran off a batch of 40, BBWC (148gr) using the Big Moose method and it does take a bit more time but produces really nice even crimping. Thanks to all for the good information.

JonF

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Armed and Dangerous

I found that a medium crimp is all that is needed with a copper jacketed bullet to stay put. A hard crimp may damage the copper and bullet.

On the other hand , you can put the hurt on a lead bullet and not harm any thing......
Anything from no belling to a "Hello there" can work with lead bullets, but................

A very heavy crimp can/may add fps/pressure to a load and put it over the edge.......... Been there done that !!

Generally, start with a very X-lite crimp and add pressure as the fps and pressures get higher, in order to keep the bullets from jumping from the case from recoil.

When I use plated bullets, any crimp at all leaves an impression in the plating. Some may view this as "digging into the side of the bullet", which technically it is, but is also a normal crimp.

I think crimp is more performance based. Obviously, keyholing or tumbling would be an indication of too much crimp, and a visual check gives a bit of a clue.

Really a chrono is needed to get a definitive answer, isn't it?

I crimp mine for consistent start pressures.

A good crimp even on light target loads equals best accuracy for my wheel gun rounds.

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GOA
USA Shooting Supporter

Ditto...

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Dave
SWCA #2465

Thanks for that image. I had seen it before but never able to print it. Actually looks like I'm doing things correctly.

Don't worry about trimming your 38 brass, you can if it makes you feel better but I used all sorts of mixed brass with different lengths and they will all shoot out to 50 yards or beyond. There are so many other things going on with a revolver that make it different than a high power rifle super accuracy sort of application.

As I recall, all the Berry's plated bullets in .38 do not have a cannelure (indented 'waistline'). Berry's specifically says on their website not to crimp to the point that you are cutting into their copper plating. So, if you load their bullets in .38 Special, which I do, the crimp is just enough to take out the belling.

I cast my own lead bullets and am using a RN, a WC and a SWC - - I size everything to .358 to keep things consistent. I use the Lee 4 die set - I seat in one operation and then use the FC die. I just put a "moderate" roll crimp on all of them - they all shoot well out of my pistols.

I'm fairly new to reloading but I think sometimes, some folks get in a hurry and have their dies set too deep. I also am loading 9mm. From the "get go" - I loaded dummy loads to get my dies set properly in the turret plate (using a Lee 4 hole). On seating - start high and gradually adjust until the top of the rim is at the top or very near the top of the crimp groove and keep checking to the recommended COAL. (I seat and then crimp - 2 operations). On the crimp die - set high and try - slight adjustments down until you have the roll crimp you want to achieve. Use the same dummy cartridge when adjusting the crimp die and you will be able to see the progression of the roll crimp.

I'm using a variety of "range brass" - some casings I've shot and some I purchased that have been shot and picked up by others. I have a trimmer but have never used it and probably won't unless I end up with some brass that is way out of whack. All of my mixed brass has rolled crimped just fine.

I'm just a "plinker" and not a competitive shooter. I don't have a chronograph and when I cast - I don't have a thermometer to check the lead that I'm using. For what I'm shooting, it all works out well and I have six 38s/357s that I use my reloads in and they all shoot well with the reloads. If I were a "competitive" shooter - then I probably would be a little more into the technology that's available as I understand the importance of consistent loads, crimps, etc. - but for the type of shooting I do, those things just don't seem to make a difference in my results.

As a fairly new reloader - and I'm 61 - I will make this comment. When starting, I read a lot, asked a lot of questions, etc. - which everyone should to in order to reload safely. However, after getting my feet wet - I found that I was "overly concerned" in regards to some of the aspects of the actual reloading - which dies, which crimp. how much crimp, etc. That's not being critical of anyone - those were my experiences. Now, after doing some reloading, playing with the different bullet types, working up charges and loads, etc. - it's like anything else - once you get your feet wet - you gain a better understanding of the process (within the limits of safety) and you begin to see the factors that can/could affect the results of the reloaded cartridge. To me, that's where the fun is coming in and I'm really enjoying playing with those things - crimp, min to max loads, etc. and seeing how they work in my handguns. Personally, I'm not out to make "hot" loads - just decent light to medium ones that will shoot accurately - or at least as accurate as I am with the eyes that I have.

As an added note - I picked up one of the Lee molds for the tumble lubed 158 gr SWC. The TL grooves on it do not appear as deep as the other bullet styles I have molds for with the conventional lube and crump grooves. On a post somewhere, I spotted where a fellow roll crimps in to the top lube lube groove. I questioned if the groove was deep enough to roll crimp in to and I found that it was a very simple process to do - no harder than a conventional crimp groove. I put a moderate roll crimp in to it and have it over 3.2 gr of BE - they shoot fine out of my Smiths - 4" Combat Masterpiece - a 5" Smith pre-10, my Model 36 snub. I'm still working with it and my next step is to try and tune the charge up at an indoor range (it's too cold outside here). I have a feeling that the sweet wpot is going to be about 3.4 gr. I still need to try them in my New Vaquero and my Smith M & P Target model. I'm tumble lubing them in a combination of Alox/paste wax and so far - no leading problems.