"Factory Crimp Die"

[Edd]

Here is a different opinion Google found. I believe it was written by Bart Bobbit.

Consider what happens when the Lee factory-crimp die is used. Take a bullet that's perfectly round and has a homogenous lead core inside of a uniformly thick jacket. Now take a case whose neck wall thickness varies only .0005". Then take the lee collet type factory-crimp die whose collet jaw dimensions vary a thousandth of an inch. Next, put this `near perfect' bullet in the
case mouth and close the Lee collet around it. The dimensional variables add directly and we have a thousandth of an inch or so difference in radius dimensions from the center of the bullet to the jaws of the Lee collet die and we're applying pressure radially to the bullet. The soft jacket and softer core reduce in diameter; the core stays at its smallest dimension and the jacket springs back a little. We end up with a bullet that's been reduced in diameter at various places around it and those dimensions are not the same; the bullet no longer has its center of mass aligned with its center of form. This adds up to an unbalanced bullet before it's even loaded and fired. Unbalanced bullets don't shoot straight. Competition bullets typically are round to less than .0001-in. and their jacket thickness has the same dimensional tolerance. All that perfection has been squeezed away when a non-perfect collet clamps down on non-uniform case necks. Even the military arsenals quit crimping their match ammo in the 1950s because
accuracy improved about two-fold when the bullets were no longer deformed by crimping. The arsenals also found out that velocity spread was higher as the crimp added another variable; release tension wasn't as uniform as when the bullets were sealed in place with an asphalt sealer.

If folks get better accuracy with Lee's factory-crimp die, that's fine by me. But I also think if they evaluated their reloading tools and the way they're used, improvements in accuracy could be had that would negate the use of the factory-crimp die. Of course Lee wants their products to be considered worthy of purchasing. Whatever marketing scheme they come up with that sells their products will certainly increase their revenues. But knowledgable accuracy buffs wouldn't dream of deforming top-quality bullets
with anything; sledge hammer, hydraulic jack, or Lee's factory-crimp die.

 

[gohring3006]

Ive read Bart's reply on that thread, but I also read 100 other reports of better accuracy and ES. That's why I'm going to test it. I'm also going to test if I have to adjust BC at long range to see if the bullet deformation has a effect on it. Honestly I don't see how a slight crimp can harm the balance because a bullet has a tendency of slumping up in the bore when fired and slammed into the lead, especially lead core bullets. I don't see it being anymore influential than the lands engraving the bullet. I also didn't read anywhere that Bart has tested the crimp, and I read several that have...

It's easy to speculate...



Edited to add... I'm talking about a slight but effective crimp, not standing on the press handle..

 

[Pdvdh]

Yes, as explained. The Lee FCD is a collet style crimping die. It's sole purpose is to crimp cases, and it does so with a lot of flexibility in adjustment. Way user friendly compared to roll or taper crimping, in my opinion.
After the shells are prepared with bullets seated to the selected depth using your favorite resizing and bullet seating dies, you'll then apply the crimp using the FCD.

 

[catamountsierra]

I think that may be the case if you over crimp, which the die is plenty capable of doing. That is why I use a fairly light crimp. I have seen accuracy go downhill with too much crimp, as well as pressure signs start to show up. You shouldn't be crimping it hard enough to create a cannelure; just crimp it enough to firmly hold the bullet.

 

[Buckskinner]

There's the Lee slamming! I knew it would show up...

I don't really care what someone "thinks" about the process, just what the results are. I have no gain from a Lee die working better than another or if crimping makes for better accuracy or not. For that matter I wish it would not so there would be one less step!!!

As stated, only a slight crimp is needed.

 

[Pdvdh]

Testing the affect of the FCD on your prized load is very simple and straightforward. Apply the crimp using the die on some of your super duper reloads. Then go shoot them side by side on paper at a long enough distance to see any improvement in precision.
If it improves precision - smile.
If it doesn't improve precision, don't bother with it any further and you're out $10.

You can try to sort out all the gibberish from the forum experts that have never tried it. What you'll find is that those who haven't tried the FCD pooh pooh it based on their preconceived belief system. Those who have used the FCD and find it beneficial to precision, continue to crimp. If you're unwilling to risk $10 to try it, then you may sleep better at night with that extra $10 in your wallet?
On the other hand, you may go sleepless wondering what $10 might have brought to your favorite pastime hobby. Hmmmmm...

 

[Deleted member 46119]

I have to agree with Paul here.

Even though I don't crimp any rifle cartridges, I am more interested now.

Testing the affect of the FCD on your prized load is very simple and straightforward. Apply the crimp using the die on some of your super duper reloads. Then go shoot them side by side on paper at a long enough distance to see any improvement in precision.
If it improves precision - smile.
If it doesn't improve precision, don't bother with it any further and you're out $10.

You can try to sort out all the gibberish from the forum experts that have never tried it. What you'll find is that those who haven't tried the FCD pooh pooh it based on their preconceived belief system. Those who have used the FCD and find it beneficial to precision, continue to crimp. If you're unwilling to risk $10 to try it, then you may sleep better at night with that extra $10 in your wallet?
On the other hand, you may go sleepless wondering what $10 might have brought to your favorite pastime hobby. Hmmmmm...

 

[rcoody]

Well my experience is all these different methods of reloading can produce quality reloads.

People.on these forums are very opinionated and voice their opinions aggressively

My thoughts are whatever works for you. Differsnt strokes for different folks.

Just because you wouldn't choose to do it that way or it didn't work for you doesn't mean the next fellow won't have success with it

Lighten up guys

 

[Deleted member 46119]

Well my experience is all these different methods of reloading can produce quality reloads.

People.on these forums are very opinionated and voice their opinions aggressively

My thoughts are whatever works for you. Differsnt strokes for different folks.

Just because you wouldn't choose to do it that way or it didn't work for you doesn't mean the next fellow won't have success with it

Lighten up guys

That's for sure.

I'm in the world of sharing what my experiences are. I don't think anything or method I do is perfect or should be used by anyone else.

My goal is to share, if it helps you or keeps you from spending money you don't want to great.

 

[Pdvdh]

Lighten up guys

I never knew it got heavy. If you're sensitive to this Thread, you better grab your sedatives before participating in the rest of them.

 

[gohring3006]

With all due respect, I never once thought this thread was getting out of hand.
It's rather mild compared to other "discussions"....

 

[RockyMtnMT]

Yep I thought this one has gone great. I never called anybody names or anything.

Seriously, good info from all involved.

I had said earlier that I am advocating a crimp with our bullets, but I have shot way more without a crimp that with. I learned how to reload 25 years ago and just did my first crimp a few months ago. More shooting and testing yet to come, but from what we have seen so far I suspect that we will add a spot on our web page officially stating that we recommend it. Our situation is slightly different than conventional bullets due to the fact that there is fractionally less surface contact with the neck of the case. So our concern first is to prevent bullet migration. Which has only been a problem with compressed loads. We did not want to change the load as it was performing very well, so we crimped it to see what would happen. Cured the bullet migration with no detrimental effect on accuracy. We have a customer 308 currently that has been giving us some trouble with random large groups. Next move is to crimp the load and see if it will settle it down.

Steve

 

[gohring3006]

Yep I thought this one has gone great. I never called anybody names or anything.

Seriously, good info from all involved.

I had said earlier that I am advocating a crimp with our bullets, but I have shot way more without a crimp that with. I learned how to reload 25 years ago and just did my first crimp a few months ago. More shooting and testing yet to come, but from what we have seen so far I suspect that we will add a spot on our web page officially stating that we recommend it. Our situation is slightly different than conventional bullets due to the fact that there is fractionally less surface contact with the neck of the case. So our concern first is to prevent bullet migration. Which has only been a problem with compressed loads. We did not want to change the load as it was performing very well, so we crimped it to see what would happen. Cured the bullet migration with no detrimental effect on accuracy. We have a customer 308 currently that has been giving us some trouble with random large groups. Next move is to crimp the load and see if it will settle it down.

Steve

I hope to get out and test this weekend. Be sure to let us know how it turns out when you try crimping.

 

[gohring3006]

Got out today and shot some comparisons.
I didn't get to Chrony any loads, the range was busy and I didn't want to mess with it. (Gotta get me a Magnetto speed, or lab radar)...
I shot five not crimped, and five crimp allowing my barrel to cool completely for each shot.
The 300 Weatherby tightened up quite a bit. It was a good reliable 3/4 Moa gun with several loads, and the five crimped loads went into a 1 1/4" group at 300 yards!!! That's the best that rifle has ever shot. That was with a hex coated 225 ELD. I'm going to load up 40 and crimp all of them to really get some good data.
The 30-06 seemed to improve some, but it will shoot in the .3s with three shots without a crimp, and it seemed to be its old self maybe slightly better, because I was able to put all five of the crimped shots in about the same size group. (.3s).. I'll have to load more to get more data. Probably do the same thing as the Weatherby and load 40 or so to test.
The 6.5 Creemoor, well I can't tell because that thing shoots dang near five shots in the same hole, and I didn't see a change with the crimp.

So far, I can see that crimping didn't hurt my groups, and one rifle got noticeably tighter.

I want to Chrony some, and test at 800 to 1000 yard to see if the slight bullet deformation affects BC.