.38sp brass folding when crimping

[gacajun]

I have a Lee turret press and reload .38sp cowboy loads. I am loading 158 RNFP to OAL of 1.53. I am using mixed headstamp brass that has been reloaded various numbers of times, I bought the brass as once fired range pickup but you never really know how many times they have been reloaded.

A have had the sides of several pieces of brass to fold over when I run them through the crimp die. What would cause this?

I think it might be just brass that has been reloaded a number of times and the sides are just not as thick as they were when they were new. Maybe the stress of crimping bends the sides.

Any suggestions?

 

[jtmo3]

Check the adjustments on the crimp die. Something doesn't sound like it set up right. Do any rounds come out ok?

 

[engineermike]

If you are trying to seat and crimp at the same time this might be your problem. If it is then seat and crimp in two separate steps and see if that fixes the problem. If you are not seating and crimping in one step then readjust your crimp die it might be set to far down and you are crimping to much. Seating and crimping in two separate steps fixed my problem.

 

[joneb]

Has the brass been trimmed to a consistent length after sizing ?

 

[jfh]

A contributing problem may be brass LOAs, particularly if you are trying to put in a strong roll crimp. Is this with a three-die or four-die setup? The "fixit" procedure varies a bit for the different setups--but for now, try backing out the body of the #3 / combined seater-crimper die, and backing up the seating stem as well. Try doing this in, say, 1/4-turn increments on the body, and then bringing the stem in. You may need to back the stem 'way out' and slowly start bringing it it....

Now, give us some more details--3 die? 4 die? die set brand? using FCD as #4? That kind of info.

Jim H.

 

[Steve C]

Exactly what do you mean by "folding over". A picture of the condition would help.

Brass will fold if there's not enough flare or belling of the case mouth and the bullet catches the edge of the case mouth when its being seated. You can also get folds in the case wall if the case isn't expanded enough after sizing to accommodate lead bullets. A +.001" diameter expander or one for lead bullets like that found in cowboy dies may be needed.

Brass can also fold if too much crimp is used. After the mouth is folded into the crimping groove the brass must give somewhere if crimp continues to be applied.

 

[Walkalong]

Case length and case mouth position in relation to the crimp groove/cannelure is critical to good crimps using a roll crimp, especially a heavy one. If the case mouth does not have somewhere to go, it can get ugly with a heavy roll crimp.

Pics would help a lot.

 

[rcmodel]

I agree "folding over" is about 100% chance of the bullet catching on the case mouth as it is seated.
It has nothing to do with crimp.

You need to bell your cases more so bullets can be hand started straight in the case before seating.

Buckles or wrinkles below the case mouth are caused by too much crimp, or mixed case lengths.
Too long cases with wrinkle when crimped the same amount as normal length cases.

rc

 

[gacajun]

delete

 

[gacajun]

Ok, finally had a chance to check this. First, thanks for all the replies, I knew you guys would have some suggestions...lots of knowledge on this forum.

I am using a 4 Lee carbide die set, there is a separate bullet setting die and crimp die. Most of my rounds come out just fine. I loaded 400 rounds two days ago and had about 10-15 the had folds in them.

The puzzling thing to me is that most of the rounds were fine, it was just an occasional one would fold over. This would indicate to me that the dies are set correctly if most were fine. I am guessing that there are just some pieces of brass with thin sidewalls but I don't know for sure.

In reading the comments, I don't know if the brass is folding on the bullet seating or the crimp, I'm not sure. I always run each case through the sizing die, then the charging die also. The charging die does bell the cases. I don't normally have a problem seating the bullet due to case diameter being too small but there could be some problems I am not seeing. Another possibility is that maybe some of the lead bullets I am loading are irregular in diameter, maybe a little larger than the rest of them. The dies are set and will always bell the case to the same diameter, the only variable here that I can see is the bullet diameter.

I do not check the OAL on the cases, just the final round to ensure that they cycle correctly through my Marlin 1894 chambered in .357. I shot .38sp in it because it is cheaper than shooting .357. That rifle is very sensitive to OAL for the round as it does not cycle the .38sp rounds well from the tube to the chamber if the OAL is not close to .357 size. I have about 3000 pieces of this brass and I shoot about 200 a week. I collect a month's worth of brass from my weekly competitive shoots and the process them all at one time.

Again, any comments are welcome.

 

[rcmodel]

The dies are set and will always bell the case to the same diameter

No, they won't.

If you set the expander/belling die with average length or over-max length cases, shorter cases will not get belled enough, or at all.

First, lets make sure we are not confusing Expanding with Belling the case mouth.
Two different things.

Expanding only expands the neck after sizing, and makes the case neck tension all the same, and is not case length dependent.

Belling is actually creating a flare on the end of the case mouth like a funnel, so the lead bullet can slide in easily without driving bands catching on the case mouth.

The expander also does the belling, but only if it is adjusted down far enough to do it.

I still think your mixed brand cases are different lengths all over the place, and the shorter ones are not getting belled enough to prevent the bullets from catching, and folding or tearing the case mouth.

Measure a bunch of different head-stamp cases after FL sizing, but before expanding & belling.

SAAMI MAX length is 1.155".
Trim Too or MIN length is 1.149".
That is only .006" between too short and too long.

And even .006" variation in case length will change the amount of bell and later, crimp it gets.

Your choices are only one of two things.
1. Trim all the cases to the same length.
2. Or sort out all the cases that are different length, and adjust the expanding & belling die, and the crimp die accordingly to each length.

rc

 

[Walkalong]

Yep, set the expander so even the shortest cases get enough bell.

 

[joneb]

Your choices are only one of two things.
1. Trim all the cases to the same length.
2. Or sort out all the cases that are different length, and adjust the expanding & belling die, and the crimp die accordingly to each length.

I agree.

In the picture below the first case from the left has a case mouth that is not perpendicular to the long axis of the case body, resulting in a uneven flare.
The second case has to little flare caused by improperly adjusted die or a short case.
The third case has about the correct amount of flare.

The fourth case has to much flare, caused by a improperly adjusted die or a long case.


For a consistent flare and crimp the case lengths need to be close, I'm happy if they are with in + or - .002".

 

[gacajun]

Never thought about variable case lengths. Let me go back and work on that. I'll sort out casings by headstamp and them group them by case lengths and load a group of each. Hopefully I can narrow it down.