factory crimp question

Lee's FCD (Factory Crimp Die) performs two functions. Crimping and post-sizing. The two operations are independent of one another and cometimes work at cross-purposes. With lead bullets, sometimes the post-sizing reduces the grip the case has on the bullet. The grip the case has on the bullet is important for three reasons.

1) It keeps the bullet from being knocked deeper into the case during handling and very important, during feeding. This is most significant in autoloaders

2) It keeps the bullet from being pulled out of the case during handling, and very important, during recoil of its brother rounds. This is most significant in revolvers.

3) It keeps the bullet from moving out of the case until a threshold of pressure has been reached. This is most significant with slow powders, but important with all powders.

In taper-crimped cartridges, the bullet tension (the grip the case has on the bullet) is provided by friction more than by crimp. If you post-size a case onto a lead bullet, the case springs back more than the lead does, reducing bullet tension. This is less problematic with jacketed bullets than with lead, but can occur with either.

If your dies are adjusted correctly, the Lee FCD will NOT post-size your loaded cartridges. You will be able to tell if it is by carefully feeling the resistance as you run the cartridge into and out of the die.

The main reason for the existence of a crimp die that operates separate from the (usual) seat/crimp combination die is to simplify installing and adjusting those dies and to prevent the case mouth from digging into the sides of bullet as it is being seated. (This can happen with a strong crimp - mainly roll crimp - on a bullet while it is still being pushed deeper into the case by the seating plug. This is virtually unavoidable with the combo die, but if it is moderate presents no problem.)

I suggest reading these threads:

Not necessary 99% of the time, but convenient.

Lee Precision's thoughts on the matter can be found in these threads:

One thread contains a lively discussion of the FCD and the function of the post-sizing carbide ring in the FCD. The phrase "9mm" is in the thread title, but don't let that dissuade you. It contains responses direct from Lee Precision, too. Read the whole thing. It is worth it.
http://thefiringline.com/forums/showthread.php?t=465091

this thread contains a poll

http://thefiringline.com/forums/showthread.php?t=465603

The Virtue and the Vice
http://thefiringline.com/forums/showthread.php?t=509934
http://www.thehighroad.org/showthread.php?t=691050
http://www.rugerforum.com/phpBB3/vie...?f=11&t=168362
http://rugerforum.net/reloading/6586...tml#post814465

Lost Sheep

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Roll Crimp

I have an old roll crimp machine. You've probably seen them. They clamp to a table top and have a handcrank.

Is it possible to roll crimp a plastic shot shell?

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Crimp Groove on an Auto Boolit

Voters8. You may not vote on this poll

On a different thread, Crimpin on the groove, I posted a comment about crimping the boolit into the crimp groove using it as a depth gauge and putting a slight taper crimp on it so it headspaces correctly as the question was about a crimp groove. A couple of people commented that they had never seen a crimp groove on an auto boolit and I guess this is the first ones I have bought that have them but didn't realize it so I thought I would post a picture of the boolit and ask "Is this indeed a crimp groove"?

Missouri Bullet Company IDP #4-XD 200gr RNFP .452
It sure looks like one to me.
BTW: I works great seated into the "crimp groove" in my Kahr over 4.2gr of Promo.

Yes it is a crimp grove. That is the Magma 45-200-rnfp. Good for both revolvers and 45 acp. Usually works well in the acp when crimped slightly into the grove. You need to hold your dimension on the case mouth. For head space.
acp dies I have (Dillon) does not have a seat plug that centers the rnfp very well. You may wish to modify your plug with epoxy or get a revolver seat plug. Just make sure you can get the bullets straight.

I have that mold btw. It's a great shooter in acp and smacks hard.

Yep....crimp groove on a 45 ACP boolit as it is more than likely meant for a 45 Colt. This doesn't mean the boolit can't be used for the 45 auto though. I actually designed a 45ACP/45 Colt boolit for my needs and it's running in at about 225 grains. Very accurate in the ruger flat top 45 revolver with either the 45 Colt cylinder or the 45 ACP cylinder and the design does very nice in the 45 colt lever action rifle as well as in the 45 ACP pistol.

http://www.accuratemolds.com/bullet_detail.php?bullet=45-225B-D.png

I don't crimp in the crimp groove for the auto as I designed it to be crimped about in the middle of the front drive band.

Missouri Bullet Company IDP #4-XD 200gr RNFP .452
It sure looks like one to me.
BTW: I works great seated into the "crimp groove" in my Kahr over 4.2gr of Promo.What is your COAL with that boolit design?

I'm running it at 1.173 and taper crimping it to .474. Goes in with just a little push.
BTW: MBC markets this boolit as being designed specifically for a Springfield XD. I also checked some Berrys Boolits also in RNFP and 200gr that I haven't used yet and they look identical to these, crimp groove and all.
Guess the question which I didn't think of when ordering them was why if it was for an XD it had a crimp groove?

I believe that is a design for the 45 long Colt to be used in lever actions in cowboy action shooting with low recoil.
It may work in 45 ACP but should be taper crimped since that is what the designer of the cartridge and firearm intended.
I also think the bit about the design being for the XD is a marketing technique, a call to Magma can establish the truth of this claim.

Since max SAAMI spec for case mouth diameter in 45 ACP is .473" the case mouth should be crimped to at or below that figure. Most use around .471-.470" or so as an average, as this crimps both short and long cases and turns the case mouth flare in.

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Abbreviations used in Reloading
Pointed Soft Point "Core Lokt"

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Keith style crimp groove

Boolit Mold Join DateMar 2013Posts4

I am loading 245g Keith style bullets in 44 mag. My Lyman #49 manual says the OAL should be 1.71 inches. That's not even getting me close to the crimp groove. Would probably need to seat it another .15 or .2 to get there. Over 10g of unique I have case to spare, but maybe not 23g of 296. So seat to crimp, or seat to suggested OAL?

Welcome to the forum!!!!.........crimp in the crimp groove and work up your loads.

Ignore all the OAL figures in books. Use the crimp groove.

Welcome to the forum and +1 to whats above. Try some 2400 under that boolit next.

10-x

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Abbreviations used in Reloading
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case crimp resizing bullets on way out...

Boolit Mold Join DateMar 2013LocationW. Central INPosts8

I cast some 429640 HPGC out of straight lead.
Sized to .431, load and pull.....from crimp groove to GC now .429.
Front band still at .431, gc still at .431...middle undersize at .429.
accuracy about 3.5" @ 50yds with 2x scope/bags.....SW 629-4 PC scope only gun.

Tried same with some BT's plain base (bhn 21) I had around, and these did not resize.
Tried with a comercial hard cast SWC (bhn about 18), and these did not resize down either.

Loaded 1st bullets (pure lead) into fired cases that I belled just enough to remove remaining crimp.
Roll crimped and pulled these and they resized to .429 from crimp groove to gc again.

So, the crimp is resizing straight lead bullets from CG to GC.
I'd like to keep these as soft as possible, but think I'd do well to harden enough that they remain full size when passing crimp.
Going to mix some 50/50 Lyman #2/Lead (bhn about 12) and try that.......

Anyone have thoughts to share........

We'll just assume up front that I'm nuts and go from there!!!!

Boolit Master Join DateNov 2009Posts849

I don't know why you insist on them being pure lead that might help. When you fire a round the crimp should iron out unless you are using light loads. If that is the case, why are you crimping so much? With a light load they are not going to come forward even with five other rounds having been fired. I might suggest a light taper crimp.

1. My ex-Lee seating dies would make skinny boolits out of fat ones, as did one RCBS. And, that was done to boolits cast of wheel weights.

2. Do you seat and crimp in one step? If so, do it in two.

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Abbreviations used in Reloading
Pointed Soft Point "Core Lokt"

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32-20 crimp and xtp or cast ?

Savage bolt gun, clip magazine? You may be fine without the roll crimp.
I use to load for a Martini action 32-20, currently loading for a Winnie 92 25-20 and both cases only give the slightest taper crimp. Mostly in the interest of case life, and both do group a little better.

If you want to stay at high end loads best stay with "J words", be ready for your cases to streach real fast.
Hope yah got a trimmer.

But I reckon the 32-20 and 25-20 show there true magic when allowed to relax and throw cast bullet with a good meplat out at around the 1400fps range.
Will kill small game just as dead, without spreading the animal accross the pasture.
Moderate loads, kind on cases, kind on old guns kind on hearing and don't clear the whole area out.

If you need flat shooting, another caliber may be in order. JMO.

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