.223/5.56 cases crushing in Lee FCD

[LaynexSiren]

Hello everyone,

Long time lurker, first time post.

I'm 2k rounds into reloading .223/5.56 and just recently (last 500 rounds) had my Lee FCD start squashing cases right at the base of the neck. All the other posts I've seen say that the Lee FCD is supposed to fix this issue, not cause it. Here's my setup:

Lee 3-die set (full length resize, bullet seater, FCD)
Lee single stage press
Using Capitol Cartridge mixed range brass, tumbled and lubed with One Shot for resizing then wiped clean for primer pocket chamfering and trimming
Speer FMJ 55gr bullets with canneleure - I'm not seating to the canneleure (too short OAL in my opinion) but to about 2.25", which cycles just fine in my rifle
All cases trimmed to a max length of 1.75"
Using a light/medium crimp, putting die against ram + 1/3 turn and locking it in

What's happening is I'll be crimping just fine and then suddenly one crimp will sound like something is rattling in the die. If I try to crimp more rounds after that, they'll all get crushed to the point that they won't go into a chamber gauge and I have to pull the bullets. I have to remove the FCD, bang it against my bench, and reseat it for it to work again. It's happening now every 40-50 rounds and used to never do this.

My only change in technique is in my case trimming. My first 1k+ rounds were all trimmed with a Lee trimmer on my power drill, then the mouth edges were chamfered. I've now switched to the World's Finest Trimmer and I'm not chamfering the mouths anymore as the WFT does a pretty good job of keeping the mouths clean.

So does anyone know what the FCD is doing that's causing the cases to crush? The rattling sound has me really confused.

Sorry this is long, thank you for reading!

 

[Blue68f100]

I don't use the LFCD. Its purpose is not to fix a problem like most use it for. Learn to setup your dies correctly and you will not need it. Been at this for nearly 40 yrs and don't use one. I don't crimp any of my AR rounds, neck tension holds the bullet.

You need to take it apart and clean it. Then lube it back up. Check for burrs while you got it apart.

 

[dh1633pm]

Its all about the amount of pressure your using on the handle. No full length pulls required. Not that I am saying your doing that. You need enough pressure to make the crimp but not enough to crush the case.

 

[forty_caliber]

Sounds like something slipped.

Adjustment on the FCD is finicky and Lee's setup instructions are misleading at best.

If you look down through the top of the die you can see the fingers of the collet. The negative space between the fingers is the key. Adjust the die so that when the ram is at full stroke with brass the space between the fingers is reduced by no more than half. Take your time and sneak up on it.

.40

 

[sevt_chevelle]

I don't use Lee factory crimp dies for anything yet I still somehow remain problem free.

 

[243winxb]

https://support.leeprecision.net/en/searchThe Factory Crimp Die coming apart is a result of the Crimp Sleeve Collet being collapsed. This is caused by closing the die in the press without having a case in the die or possibly by having the die adjusted too deeply in the press. The Crimp Collet needs to be sprung back open. https://support.leeprecision.net/en/knowledgebase/article/factory-crimp-die-coming-apart

Lee has crushed shoulder info on the website, i cant find it right now. read over the factory adjustment instructions again.

I read the FCD has been changed. Doesn't size as much of the rifle case neck??

I don't own a Lee.

 

[Walkalong]

The Lee FCD for bottle necked rifle cases doesn't "fix" things like that, you're thinking of the standard FCD for pistols.

The Lee FCD for rifle uses a collet crimp with no "post sizing" ring.

It's crimping too early and buckling cases.

 

[Walkalong]

https://support.leeprecision.net/en/searchThe Factory Crimp Die coming apart is a result of the Crimp Sleeve Collet being collapsed. This is caused by closing the die in the press without having a case in the die or possibly by having the die adjusted too deeply in the press. The Crimp Collet needs to be sprung back open. https://support.leeprecision.net/en/knowledgebase/article/factory-crimp-die-coming-apart

Interesting, and could be the issue.

 

[243winxb]

Found it. May not be the problem?

Crushed and/or buckled case.

If the collet in the die has been collapsed, the case neck can not clearly enter the collet area. This results in a crushed and/or buckled case. This can be avoided by not operating the die without a case in it. If this happens, it is necessary to remove the collet and pry the collet leaves back so that they stay apart when inserted back into the die. The ID of the die body will cause the leaves to stay uniformity apart.

I have never found a need to crimp 223/5.56 shell for M16, Mini14 and others. Neck tension should be enough. After seating a bullet, the neck diameter should be larger by .002" minimum. This provide minimum bullet pull of 35 lbs.

Test- measure COL, chamber the round, measure COL again. Has the COL gotten longer? If some, may need more neck tension or a crimp.

 

[LaynexSiren]

Found it. May not be the problem?

Crushed and/or buckled case.

If the collet in the die has been collapsed, the case neck can not clearly enter the collet area. This results in a crushed and/or buckled case. This can be avoided by not operating the die without a case in it. If this happens, it is necessary to remove the collet and pry the collet leaves back so that they stay apart when inserted back into the die. The ID of the die body will cause the leaves to stay uniformity apart.

I have never found a need to crimp 223/5.56 shell for M16, Mini14 and others. Neck tension should be enough. After seating a bullet, the neck diameter should be larger by .002" minimum. This provide minimum bullet pull of 35 lbs.

Test- measure COL, chamber the round, measure COL again. Has the COL gotten longer? If some, may need more neck tension or a crimp.

Thank you so much for all the help! I'll do the chamber test on a round that's not crimped and see if OAL changes. Removing a stage in reloading would be nice!