9mm versus Factory Crimp Die - WHY?

[leadchucker]

There is some underlying theory to the design of these dies, and I'm not really understanding it.


Example:
According to the drawings, a 380 ACP is a straight case, with no taper. The bullet is just a press fit into the case, perhaps causing some slight case bulging. The case has no "crimp." It has to be flared slightly to allow the bullet to be seated, but all that is really needed beyond that, is to eliminate any remains of this flare. The round is complete then. Right?

Cases come out of the sizer/decapper at .371 - .372 base outside diameter, and .370 mouth outside diameter.
I have the powder through die set to flare the mouth to about .374 -375 outside diameter, for a .356 - .357 inside diameter, to allow room to set the bullet.

I can set the outer section of the bullet seating die set to just barely touch the mouth of the case. That seems to be just enough to bring the outside diameter of the mouth of the case after seating the bullet to about .373. That's about the same diameter as the rest of the case where the bullet is seated. It seems that all this die is really supposed to do is to remove the remains of the flare from the mouth of the case. Right?

That's all that is needed, isn't it?

There are two adjustments on the FCD. The first, the outer section of the FCD is supposed to be set to contact the shell holder, so the round can be fully inserted through this die. I gather that the inside diameter of this section of the FCD is sort of a maximum diameter limiter? Of the few rounds I've made, only a couple have even made contact with this part of the FCD.

As to the center section of the FCD, I could set it to do about the same thing that the bullet seating die does, which is eliminate any remains of the flare. It's really redundant to the bullet seating die. Right?

Hope this makes sense. I would sure like to be sure I know what this does.

 

[LiveLife]

Wow, the FCD discussion again ...

I reload jacketed, plated, and even lead bullets without using the FCD. When I help setup a new reloader, I have them order the 3 die set unless they want the FCD "just to have it". Even with the 4 die set that includes the FCD, I have them adjust the 3 dies first so their finished rounds work. If they still want to use the FCD, they have to first prove to me that they can adjust the 3 dies so the finished rounds fit the tight chambers of my Lone Wolf barrels - but when they do, they find that FCD really doesn't do anything to their rounds.

For me, I consider the FCD as a "correction" die as mistakes made on three other dies can be "erased" by the FCD's final sizing. If I make a mistake on my dies, I want to know where/which die caused the mistake when I drop test the finished rounds in the tight Lone Wolf chambers. I do not want to rely on a "final sizing" die to correct what I have done wrong - This is not good reloading practice. I think FCD does have it's uses (push-through sizing of bulged cases for one, except tapered 9mm cases) but I endorse the reloading practice of using FCD after you have your 3 dies adjusted first.

 

[leadchucker]

I have read a fairly long list of search results for FCD, and have yet to find anything that helps me to fully understand the intent of the Lee factory crimp die, and I'm speaking of the Lee Factory Crimp Die for the pistol rounds, particularly, the 380 acp and 45 acp rounds, and possibly even the 9mm Luger round. Any other crimp and rounds may have a different intent and purpose.

According to the specifications for these rounds, they are NOT crimped per se. The mouth of the case should just be straight, and tight against the bullet. That's critical for head spacing the round. If this is incorrect, someone please correct me. Understanding this will go a long way toward making the purpose of the Lee FCD clear.

I can see that there are two points of contact between a 380 acp or 45 acp, or 9mm Luger factory crimp die, and its respective round.

First, is the ring inside the outer part of the die. The inside diameter of this ring appears to be about .373, in the case of 380, the maximum diameter of the round. Pushing a round through this would seem to assure that the round does not exceed the maximum diameter. That seems fairly straightforward and obvious. Again, if this is incorrect, someone please correct me.

But there is also the second ring inside the center part of this die, which is a separate adjustment. It's inside diameter is about .356 and it will clear the bullet. It is similar to the outer adjustment of the bullet seating die. If this ring contacts the mouth of the case, it will compress it. I assume that the intent of this is to remove any flare in the case, and nothing more. Again, if this is incorrect, someone please correct me. It will compress the mouth far too much if you adjust it too far. I've ruined several bullets and cases so far futzing with this.

 

[Walkalong]

The FCD for pistols does two things.

First, it crimps like any other die. That is adjusted with the stem.

Second, and where the debating stems from, is the carbide ring designed to "post size" any round that is too fat/crooked/whatever. It is to ensure rounds fit and feed. It does do that.

 

[Foto Joe]

+1 for bds

I think bds hit the nail on the head. If your dies are set correctly, there really isn't a use for a FCD.

For those that use them and like 'em, to each his own. Personally, I'm lazy enough that I don't really want another station on the press to deal with.

 

[snuffy]

I'll take this a step further. The "ring" in a 9mm lee factory crimp die,(FCD), is actually a sleeve, not like the doughnut shaped ring in other FCD's. It's because the 9mm is a tapered case. Don't believe that, measure the base and the mouth you'll see.

I agree if the FCD is post sizing ANY case, you have an underlying problem you need to identify and fix.

As noted, if you're loading oversized lead boolits for a reason*, the FCD will size every case, causing the lead boolit to be sized smaller as well. Some people simply knock the sizer ring/insert out of the die, making it a taper or roll crimper without any post-sizing taking place. Hint-hint, that's what some of you that have given up on the FCD can do, make it into a strictly crimping die.

I use a FCD in every semi-auto I load for. As said, IF it sizes any, I find out what's causing it, then correct it. Otherwise it's simply putting the appropriate taper crimp on the case mouth,(essentially just removing the flare + a bit more.)

 

[ranger335v]

Like any other special purpose tool, Lee's FCDs are no cure-all for every one nor does it need to be for it to be useful for those who need it. Blanket condemnation or praise for any specialty reloading tool based on MY particular and personally limited use is silly.

 

[GLOOB]

There are at least 2 instances where a Lee FCD can be desirable for pistol rounds, IME.

1. 38 special loaded with wadcutters. When you get a thick military case, the brass can swell out to the point the cartridge won't chamber easily.

2. Plated bullets. If they get shaved and the plating gets scrunched up, the cartridge won't chamber, resulting in a jam.

Of course it would be better to toss these rounds, altogether. But if you load on a progressive press and care more about reliability than accuracy, an FCD will save you time over a proper chamber check.

 

[Sam1911]

What I do like about using the FCD is the post sizing ring. I shoot competition and I like to use the post sizing ring as a case gage.

Yes indeed!

I use them for .45 ACP and 9mm. I would be perfectly happy not to use them, but there they are, and they are cheap belt-and-suspenders insurance.

I have pals who are serious competitors (or at least enthusiastic ones ) who gauge every loaded round before a match. I trust the FCD to do that job for me just before the round leaves the press. I've never had a loaded round that went through one that wouldn't chamber. Maybe it helps. Maybe I'm just that good!


(... now, if only I could teach it to look for flipped-over primers! :banghead

 

[RustyFN]

+1 for bds

I think bds hit the nail on the head. If your dies are set correctly, there really isn't a use for a FCD.

So what you are saying is that nobody should seat and crimp in separate steps and use the FCD as a crimp die?

 

[Walkalong]

I did not read that anywhere.

Naturally you don't have to seat in a second step because you can crimp with the seater, but that is a personal decision whether to seat/crimp or seat and then crimp.

You can crimp in a second step with a FCD or a plain crimp die, which is another personal decision.

Bottom line is properly made rounds with bullets that are not over sized do not need the post sizing feature of the FCD.

Using inexpensive lead bullets that may be oversized? Don't want to gauge every round for IDPA this weekend? By all means use a FCD to squish em into submission.

 

[RustyFN]

I did not read that anywhere.

Naturally you don't have to seat in a second step because you can crimp with the seater, but that is a personal decision whether to seat/crimp or seat and then crimp.

You can crimp in a second step with a FCD or a plain crimp die, which is another personal decision.

Bottom line is properly made rounds with bullets that are not over sized do not need the post sizing feature of the FCD.

Using inexpensive lead bullets that may be oversized? Don't want to gauge every round for IDPA this weekend? By all means use a FCD to squish em into submission.

I didn't read it that way either. I guess it was a bad attempt at trying to make a point. My point is that the statement " If your dies are set correctly, there really isn't a use for a FCD " is false. The C in FCD stands for crimp. so even if your dies are set correctly there is a use for the FCD if you want to separate the seating and crimping steps.

Bottom line is properly made rounds with bullets that are not over sized do not need the post sizing feature of the FCD.

Correct and the FCD is not just a post sizing die, it's also a crimp die. I actually don't use any of my FCD's for the post sizing feature but I do like to use them to crimp.

Using inexpensive lead bullets that may be oversized? Don't want to gauge every round for IDPA this weekend? By all means use a FCD to squish em into submission.

I would advise against that. JMO

 

[Walkalong]

" If your dies are set correctly, there really isn't a use for a FCD " is false. The C in FCD stands for crimp. so even if your dies are set correctly there is a use for the FCD if you want to separate the seating and crimping steps.

Not false, it just recommends a regular crimper if one wants to crimp in a separate step.

Correct and the FCD is not just a post sizing die, it's also a crimp die. I actually don't use any of my FCD's for the post sizing feature but I do like to use them to crimp.

Fine, you do not want the post sizing feature, but any crimp die will work if you are not interested in the post sizing. The FCD then, is not necessary, just a crimp die is.

I would advise against that. JMO

But it's the only practical use of the FCD die. (And I have posted against doing it to "fix" rounds plenty of times. It "fixes" nothing of course, just masks it.)

Just MHO, of course.

My thoughts are pretty well known on both the crimping (Nothing wrong with the FCD crimping) and the post sizing (Only one practical use for it) features of the FCD.

I'll let you have the last word on this one. If others wish to respond to whatever you post next, you can debate with them if you wish. I'll read it with interest.

 

[LiveLife]

I have an interesting suggestion/exercise just for giggles:

All those reloaders using FCD, make some dummy rounds WITHOUT the FCD and see what the finished round dimensions are or whether they will pass the gauge test.

If they pass, then you are good to go.

If they don't pass, then you got some work to do or you can keep things as they are, it's a free country ... carry on.

Peace ...

 

[RustyFN]

I have an interesting suggestion/exercise just for giggles:

All those reloaders using FCD, make some dummy rounds WITHOUT the FCD and see what the finished round dimensions are or whether they will pass the gauge test.

If they pass, then you are good to go.

If they don't pass, then you got some work to do or you can keep things as they are, it's a free country ... carry on.

Peace ...

Been there done that, no problems. I use it because I like to seat and crimp in separate steps. I understand where you are coming from, I guess I will just never understand what is wrong with using the FCD for the crimp feature and a case gauge. I don't use rounds that get post sized, but then it's been a few years since one has been post sized. That is with jackted and lead. I don't expect everybody to use one because I like it. But then I guess I will always be wrong in the eyes of those that don't like it.

 

[1SOW]

9mm--turret press: I like it. I prefer removing the bell on the fourth die. ALL feed fire and function with good chrono results and good SD's.

In 9mm (in particular) it seems to size slightly lower on the case than the sizing die (both adjusted properly). YMMV.

Run a test (9mm only). Size a range pick up case that looks slightly over-expanded. Measure the length. Run that case through the LFC die, and measure it again. Not always, but on those high pressure/poor case support cases it'll be longer after going through the FCD.

Good or bad is the reloaders opinion.

 

[Foto Joe]

So what you are saying is that nobody should seat and crimp in separate steps and use the FCD as a crimp die?

Not at all. Like others before me, I may have not used the perfect language to get my point across. Remember, there are MANY people reading these posts who A: Have Never Registered on THR, B: Have little or no knowledge of reloading but might want to "Try This At Home".

I think the point that I flubbed was "A Factory Crimp Die" (in my opinion) is something that you can live without if you have to. Especially for someone new to reloading who is going to have to try to decipher our conversations on this thread.

I have a FCD for 45 Colt. I've found that it makes an excellent paper weight, but I haven't seen the need for using it loading 45 Colt Black Powder Cartridges. On the other hand, I can see where using one on 9mm might have its benefits although I don't have one in that caliber yet. I'm using a single stage press for the next month or so until I get home, so adding another step isn't worth the time for me.

Here again, it's all personal preference. If you're loading match grade ammo and it's gotta be right down to a gnats posterior, then you probably want a FCD. If you're like me and simply hunt paper then maybe not so much.

 

[RustyFN]

Foto Joe
I think the point that I flubbed was "A Factory Crimp Die" (in my opinion) is something that you can live without if you have to. Especially for someone new to reloading who is going to have to try to decipher our conversations on this thread.

I have a FCD for 45 Colt. I've found that it makes an excellent paper weight, but I haven't seen the need for using it loading 45 Colt Black Powder Cartridges. On the other hand, I can see where using one on 9mm might have its benefits although I don't have one in that caliber yet. I'm using a single stage press for the next month or so until I get home, so adding another step isn't worth the time for me.

Here again, it's all personal preference. If you're loading match grade ammo and it's gotta be right down to a gnats posterior, then you probably want a FCD. If you're like me and simply hunt paper then maybe not so much.

Joe as I said I made a bad attempt at trying to make a point, sorry if it sounded worse than what I meant it to. No hard feelings I hope. I couldn't agree more with you that people can live without the FCD. But for a lot of people it is a very usefull tool. I guess it just hits a nerve sometimes when people that don't like it think that nobody should use it because they don't and then accuse the people that do use it of butchering their ammo just because they do use it. I'm sure there are people that do but for a lot of us that couldn't be farther for the truth.

 

[zeke]

If using brass of significantly different lenght, the LFC can adjust down to the shorter lengths, without buckling the longer case like a standard taper crimp die can. Just had this trouble with a mixed bag of 32 acp cases, and wasn't about to trim them little cases. Yes that is a fairly xtreme example, but it saved me the effort of seperating the cases by make, and readjusting the standard crimp die each for the short ones. It also sizes the case down slightly further than (some) of standard carbide sizing dies. I like it for cheap insurance, especially when loading mixed range pickups.

Prefer the Redding profile crimp die for roll crimping revolver cases. The LFC can size down the lead bullet too far, especially when using larger dia bullets with thicker cases (starline)

your milage and preferences may differ