Inconsistent crimp and COL for .357 Magnum

Homebrewer, you can contact Lee and see if they can help you. Lacking other info, and assuming you are adjusting the expander die to put the minimum necessary bell on the cases, there may be a problem with the expander. It does not take much belling or expansion to set up the case properly for a jacketed bullet and still retain the right tension, typically less expansion than you would use for a lead bullet.

If the problem is with the dies, Lee may be able to send you a part that fixes this. I use an RCBS 3 die set for .38 Spec, and I have no problem seating and crimping with one die in the 3rd step on a progressive Dillon 550, and did the same when I was a single stage loader.

If you cannot get enough tension to retain the bullet, it's doubtful to me that crimping in a separate step, or crimping at all will solve that problem.
 
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You can't start a .357" plug into a .354" tube without some sort of "entry way". Most reloader will slightly flare the case mouth (many use a Lyman "M" die). Sometimes you can get away with a chamfer in the case mouth and hold the bullet straight when starting it into the case.

You can get a separate crimp die if you want or simply readjust the stock seat/crimp die between seating and crimping (I have Redding Profile Crimp Dies for my revolver reloads). Really not all that involved. I used a single stage for many years and separated the seat and crimp operations using the same die (back off the crimp function, adjust seating function and seat all the bullets. Back out seating stem, readjust for crimp, crimp all cartridges.)...
 
If the problem is with the dies, Lee may be able to send you a part that fixes this.
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Don't hold your breath. When I had issues with my Lee .380 dies, their reply was to send in the die on my dime to see if there was a problem. If there was a problem, they would repair or replace the die at their discretion. They told me in advance that it was a known issue that their .380 sizing die did not correctly size some brands of brass, and that I would probably need the undersized sizing die any how. My issue was not with some brands of brass, but every brand of brass. Why would I(or anyone for that matter)want a die that would only size specific brass, when they are used to using mixed brass? I see no reason why Lee does not state this in the first place. I believe it is just a way to sell you another die. Same goes for giving only one type of seating stem. BTW, Lee will make you a custom one for $8 plus shipping(another $5), plus the cost of sending them a bullet. Same applies for why should anyone need to grind down their sizing die to get it to work properly? It should size brass correctly right out of the box or be replaced/fixed without cost to the buyer.

As I said in my first post, the OP has more than one issue going on here, seating issues and sizing/flaring issues. Some of which may be his fault, some of which may be his dies. Really hard to tell without him experimenting more or being there in person. One thing I do know. Do not count on Lee being much help without paying for it.
 
Homebrewer,

Always keep the immortal words of Charlie Papazzian in mind. "Relax. Don't worry. And have a homebrew."

OK. Here's your first issue:
Homebrewer said:
Well, I measured about 10 cases and most were between 1.580" and 1.582". A few were around 1.576" However, I didn't trim them because they are all below the trim to length of 1.585".
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No. Here's the SAAMI drawing of the .357 Magnum. The cases should measure 1.270" to 1.290". Trim-to is normally in the middle of that at 1.280". So I think you have been looking at data for a .357 Maximum, which has a case that is 1.585"-1.605", with trim-to length being 1.595" nominally.

Whichever cartridge it actually is, the cases getting shorter means you've been shooting it at low pressure. Pistol cases tend to shorten if you use them at pressures below about 30,000 psi. That's because they don't stick to the chamber at lower pressures, instead backing up into the breechface and swelling to fill the chamber, which makes them shorter and fatter. They never quite recover their length completely during resizing from that shape, so they get shorter.

Whichever cartridge it actually is, the COL irregularity and the ability to push the bullets into the case are related. When a case is not adequately narrowed during resizing, the grip it gets on the bullet is likewise inadequate. When you seat the bullet you are probably lowering the press ram immediately afterward, and the air you just compressed in the case can then push the bullet out some. If the case is tight it holds on. If it is extra loose, the air bleeds out and the bullet also stays put. There is a magic range within which the bullet is pushed back out. Try raising the ram and leaving it there for ten seconds or so to see if giving the compressed air some time to leak out at least reduces the problem.

Why are your cases failing to get snug enough? I've seen this in .45 auto cases. It's always been in cases with the R-P headstamp. They just made the brass near the mouth too thin, so as it work-hardens from repeated sizing, it is able to spring back from the resizing operation. The same thing is perfectly possible with other brands with thin necks. I'm just saying that R-P is where I saw it before, and .45 Auto is where I had bullets seem to levitate partially out of the case due to compressed air and before I got them to the crimping station.

There are two cures for the above in addition to giving the air time to bleed out. One is to replace the brass. That's probably not a bad idea anyway since you know they are short and you want to start loading full-house, which old cases won't withstand a lot of anyway. Starline makes both .357 Magnum and Maximum and their brass that I've had (.45 Auto, .38 Special, .357 Mag, 44 Special, 44 Mag) has all been of the best quality currently available. I recommend you get some of their brass specifically, even if it is just a small quantity to try (Midway and Midsouth both sell the brand, and you can buy direct from Starline for larger quantities). If the new brass works, you'll know the brass was the problem, and that will mean I was proved right a your expense. That's my favorite way of being proved right; someone else footing the bill.

The other solution is to buy a smaller diameter sizing die. Lee sizing dies that I have tend to err on the wide side of the range, presumably to avoid wearing out your brass prematurely. They should work fine with Starline brass. However, you can buy a Dillon sizing die and it will likely be smaller. That same .45 Auto brass that would not size properly in either a Lyman or a Lee or a Bonanza die, sizes just fine in a Dillon die. I think this is because the Dillon is made for a progressive press, and you can't have some cases working and not others in a progressive loading operation or you get unusable ammunition mixed in with good ammunition and everyone is getting mad at you and blaming your machine instead of the brass.

Hope this helps.
 
"Don't hold your breath. When I had issues with my Lee .380 dies, their reply was to send in the die on my dime to see if there was a problem."

Enough already with this Lee die set, sizing and belling the case mouths to load a handgun cartridge doesn't have to be this hard. OP, just get an RCBS 3 die carbide set for .357 Magnum, follow instructions carefully, and don't look back. I'll tell tell you what, if you get 'em and need help, PM me and I'll give you as much help as I can from afar.
 
Ok. I bit the bullet (pun intended) and decided to buy the RCBS carbide 3-die set from Midway. I also ordered some 158 gr bullets and Starline brass to get to the root of this problem. I ordered the Lee Factory Crimp Die, too, in case I need it.

Stay tuned and thanks for all the help so far.
 
Too bad . . .

Well, you have already spent money on buying stuff you do not need, so I will not try to go into details on how I think you may have gone wrong so far unless you specifically ask. But I did want to add these comments for your consideration:

RCBS dies are excellent dies, but you did not need them.

Lee dies are excellent dies (with features you do not get with RCBS), and you already have them. Your problems, whatever they may be, are almost certainly NOT with the dies.

Lee Factory crimp dies are very controversial - some love them, others hate them, and only a subset of folks actually seem to understand them. Personally, I rarely use them for pistol rounds and would NEVER consider using them for either lead bullets or revolver rounds.

Some folks always yell about how you really need to do bullet seat and crimp in different steps - personally I disagree very strongly. This is completely user choice. Nothing wrong if that is what you really want to do, but it is absolutely NOT needed to produce outstanding quality reloads, even heavily crimped magnums. Again, my personal preference is to ONLY seat/crimp in one step (and I prefer Lee dies).​

I wish you luck getting your issues sorted out.
 
Homebrewer, I'm assuming you can properly adjust the resizing die. At risk of writing the obvious or the redundant, here's instructions for the expander die:

"Adjusting the expander die:

First, run the shell holder to the top of its stroke, then screw the expander die into the press until the die body touches the shell holder, then tighten the large lock ring. Lower the shell holder, place a resized case in the shell holder, and run it fully into the expander die. Check the mouth of the case. It should be set so that the case is expanded and belled just enough to accept a new bullet. If the case needs more or less expansion, loosen the lock nut at the top of the die and screw the tapered expander plug up or down until the correct amount of belling at the mouth of the case is achieved, then re-tighten the lock nut."

Then, you should just be able to insert the bullet into the top of the case prior to seating, and it should have the ability to sit there and be relatively stable and vertically aligned (not cocked or wobbly). The trick is to adjust the expander plug in very small increments until you get it just right. A jacketed bullet will normally not sink into the case very deep to be set properly for seating and good positive tension.

For a lead bullet, essentially the same. The difference is that (in my experience) sometimes the belling has to be a little more for a lead bullet to seat and not shave lead or damage the softer base. Also typically (in my experience), the lead bullet will sink a little deeper when you place it on top and into the case, but positive tension should still stop it from going down too far.

If any bullet can be pushed all the way into the case with insufficient tension, then your expander plug is set too deep with excessive belling, or you have another problem (expander plug diameter is too big, brass problem, bullet diameter too small, or sizing die issue). Lets try the RCBS die set and see how it goes.
 
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Mauser69,

I bought the RCBS dies because there seems to be a possible issue with the Lee dies expanding the mouths too much and/or not seating the bullets squarely.

I bought the brass in case there's an issue with my brass which I've reloaded many times.

I bought the 158 gr bullets since I've had no problems with them in the past, only these 125 gr bullets. I had no 158 gr bullets left to try.

And, I bought the Lee FCD as insurance in case I need to seat and crimp separately.
 
Instead of the FCD try the collet crimp die. Best thing since sliced bread. Just seat the bullet with the die set enough to just remove the belling of the mouth, then crimp with collet crimper in the next step. I use them for both my .357 and .41 magnums with excellent results in both my revolvers mad levers.
 
Success!

I got my goodies from Midway and I had no issues getting my .357 Magnum rounds done perfectly. It was very easy using the RCBS dies to resize and expand the case mouths just enough to accept the bullets. Setting the bullet and crimping was also very easy. The bullets were very tight in the case even before I set the crimp. No movement at all. The amount of crimp was set just right without much trial and error. Crimp and seat in one step as advertised!

So, I didn't need the Lee FCD or the 158 gr bullets and new brass cases. But, they will not go to waste, of course.

So, what does this all mean? Are the Lee dies bad and the RCBS good? Hard to say. I had no issues in the past getting my Lee dies set up right. Why I couldn't do it this time is a mystery. But, the RCBS are are very high quality and helped me in this situation.

Thanks to all who contributed to my success.
 
"The bullets were very tight in the case even before I set the crimp. No movement at all. The amount of crimp was set just right without much trial and error. Crimp and seat in one step as advertised!"

That's how you roll when its done right.

As for the Lee dies, perhaps the setup is a little different in approach, or something is off in diameter. I have no experience with Lee dies except for a 3 die set in 9mm Mak in a die head for my Dillon 550, and they work fine, and they do seat and crimp in one step.
 
That Starline brass may solve the problem, because I was going to suggest that fired brass like Remington, R.P headstamp, can be thin and thus fail to be resized small enough to really hug the bullet, wanting to also suggest sorting your head stamps to eliminate a variable.

It is unusual for your bullets to be .357 instead of .358, assuming lead here, compounding the problem, but the fact is the expander die is designed for .357, unless RCBS or Hornady "Cowboy". Normal case wall thickness then should yield tight bullets.

If pressing bullets too hard to check tightness, the bullet lube can become a factor. The crimp is intended to be a clear roll, more than to just remove belling.

Note that a Lee FCD could be quite useful as long as your bullets are at .357 rather than larger. Otherwise there is the potential for bullet swaging by the post sizer insert, spoiling neck tension and possibly creating barrel leading.
 
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