I’ve only been handloading for pistols for a couple years. I loaded cast bullets in 357 with no problems. Bought a box of Speer 158 gr jacketed hollow points and when I seat the bullet. I crush the case. What am I doing wrong?

Maybe need to bell the case more? Ever shave lead off the cast when you were seating them?

Crimp shoulder is buckling the case.

Yep. Back the die off. The roll crimp into the canelure is a delicate process. Cases trimmed to the same length helps. If Im loading full throttle ammunition with H110/W296 for instance, I like to crimp as a seperate step from seating. Practice ammo at moderate speed can be seated and crimped together with one step. Comparison with a similar factory round can help guage how much crimp to use until you get a good feel for it.

Another guage is to back up the seating stem in the die, insert the die loosely in the press, put a loaded factory found in the shellholder, push the press lever all the way down, and then screw the die down until it makes contact with the case. This should replicate a factory crimp. I also agree to seat and
crimp separately. Assumptions are that the brass is all trimmed to the same length and that the seating is adjusted for that particular brass and bullet.

Nothing like a flame at night with a 4" . 357 loaded with H110!

Yep. This is what is happening. Roll-crimping cast bullets and roll-crimping jacketed bullets with the same die setup will cause the cases to buckle. This is because the case mouth can't get mashed into the jacketed bullet very far, so it gets crimped a bit, then buckles the case.

I just loaded them into 38 Specials. No problem.
How do I fix the roll crimping problem?

The seating die has two inside diameters. The larger dia corresponds to the cartridge dia. The smaller dia corresponds to the bullet dia.. Between those two diameters is a sharp step or shoulder. When I adjust the die to seat bullets. I screw the die down until the shoulder stops on the mouth end of a sized and belled case in the shell holder. Then I back it off. Just a turn or two for jacketed bullets. A bit more for cast lead bullets. After the bullets are seated to the desired over all length. The die can be srewed down incrementally until the shoulder just begins to roll the edge of the case mouth inward. After that, slight downward turns of the die increase the amount of crimp. Too much will buckle the case. So sneak up on it slow. When the amount of crimp is right. Tighten the die lock ring.

This is a good explanation. A simpler one is just to back the seating DIE off/out an eighth of a turn or so and see if that helps. If the problem gets better but isn't fixed, back the die off a bit more. It is important to note that backing your die out changes the seating depth of the bullet, in effect making the loaded cartridge slightly longer, so you will likely want to adjust the seating STEM down to accommodate it. One all my handgun dies where I roll-crimp using the seating die, I have two marks on my die that align to a registry point on my press: one of those marks equates to cast bullets and the amount of crimp they get, and the other is set for the amount of crimp that jacketed bullets get. Bullet seating depth is set using a dummy round.

Very good point. I forgot to include the seating stem must be adjusted in conjunction with the die body. Backed off to not change the bullet seating depth. Then returned to maintain the correct depth if seating and crimping in one step.

Get the instructions out of the die box. Follow them in sequence. There's a reason they're there. Go to your Speer Manual's handgun loading section. Read the set up and seating portions especially. Again, there's s reason they're there. Have instructions on your bench every time you load until the process is mentally imprinted. Then have them there anyway.

The guy on the internet won't be sitting on your bench every time you need him or every time you need the RIGHT answer to a question. Written instructions can always be there and 99% accurate. The other 1% probably won't do you any damage.

The ABC's of Reloading, and The Lyman Pistol & Revolver Handbook are also good reference books. For handloading one can never have too many books and loading manuals.

I followed the instructions with the dies exactly.

More flare?

Back off the roll crimp. See if that fixes it.

I adjust a pistol seating die in four steps. First I adjust the die to just bump the case. Then I seat a bullet to the correct depth. After that I raise the seating stem and turn the die in until I have the correct crimp. Finally with the ram raised I turn the stem until it is firm against the bullet. Then it is good to go.

Well you did that part right. Similar thing happened to me quite a while back so exact circumstances don't recall easily. But, it involved seating and crimping in one step. IIRC I was starting the crimp barely before the bullet was fully seated. Easy fix when I figgered it out. Good luck.

Buy a lee factory crimp die. Only use your seating die for seating then crimp with the lee.

Bb

When I adjust dies for a pistol/revolver, with the die backed out so it’s not touching anything, and with a case on the ram, I run the ram all the way up. Then I screw the die down ‘til it contacts the case mouth. Them I unscrew the die about 1/2 turn and lock it with the locking ring.

Then I seat all the bullets to a depth where the case mouth is where I want it (even with the upper-middle of the crimping groove of the bullet if I’m going to crimp) but without touching the bullet with the seating stem.

Then I’ll back out the seating stem a turn or two where it won’t touch the bullet. Then, by trial and error, start turning the seating die itself down 1/4 turn at a time to get the crimp I want. IOW, I seat the bullets to the length I want and then by backing out the seating stem, I seat the bullets and crimp in two different stepS.

Amen

What I do with 357/38 and .44 mag. Got tired of trying to deal with wrinkles.

You have to back up the die. The 357 case is longer; you have to allow for that. Your die set should have came with a spacer to use when reloading the longer 357 casings. Put that spacer between the die lock ring and the press. That is usually all you need to do...if not it is a good start.

If you are getting good results with 38 special, you are on the right track. Backing out your die will work. Also, use the spacer on all three dies. You probably will not have to redial them in...just remove the spacer when going form 357 to 38 Special.

When using lead, I always flare the mouth enough that the bullet will sit up straight when placed in the case mouth. You don't want shaved lead loading up your seater die...and as has already been suggested...I always seat and crimp in separate operations.