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eridepilot
10-04-2011, 12:39 PM
What our the differneces and advantages between roll, taper and factory crimp dies? I am reloading .223(already use a factory crimp die), .38, .357, .45 and larger.

grant22
10-04-2011, 12:54 PM
Couldn't tell you. It has been said to me that .224 is already such a tight fit into the case mouth that a crimp isn't necessary, but aides in smoother feeding. So a slight crimp is how I do it (basically kiss the case mouth).

rsrocket1
10-04-2011, 12:54 PM
Roll crimping is used only for revolver type rounds such as .38, 357, 44. These cases headspace on the rim and don't rely on the case lip to keep the cartridge from being pushed away from the breechface when the primer goes off. The roll crimp prevents the non-shooting bullets from "jumping out" from the recoil of the round being shot. It also prevents bullets being pushed in when sitting in a lever action tube magazine.

Taper crimp is used for other cartridges such as autoloading rimless cases (45ACP, 9mm, 40SW, 380 ACP). It can also be used for rifle rounds. IMO there is little need to crimp an autoloading round that sits in a box type magazine. The important thing is to size the case properly to get the right neck tension on the bullet. Crimping should not be used to hold an otherwise loose bullet, nor does it really add to the start pressure of a round. Some claim that a crimp helps make the burn more uniform. I say an adequate and uniform neck tension is more important.

Military rounds are crimped on the bullet and on the primer because they are made to withstand a lot of beating and banging in transport, probably way more than the recoil of the gun just before being fired.

Do a search for "Anyone have good pictures of what a roll crimp looks like". There is another forum that has multiple pages with pictures showing what good/inadequate/excessive crimps look like.

eridepilot
10-04-2011, 6:02 PM
Cool thanks for the info rocket.

protoolsnerd
10-04-2011, 6:07 PM
All depends on what you're doing with the round .

For instance precision rifle rounds do very little crimping save a minimal taper. You want as little interference with that round entering the barrel as possible. Don't want drag impeding it .

Where you take the above info for revolvers , semi auto , and military rounds.

For your .223 , are you using these in target matches or for less precision tactical rounds? Are they getting treated well after you press them? Or are they going to get jostled and banged around . If it's the latter i'd crimp them because you don't want that bullet working its way up or down . If it's for match target shooting , like i said , as little interference as possible .

What dies do you use ?

eridepilot
10-04-2011, 6:21 PM
Normally the .223 gets taken out to the glass factory in Santa Barbara for some morning blasting. The rounds get reloaded and tossed in an ammo can then thrown in the bed of my truck. Never had any issues with the reloads. The only reason I bring it up is the guy at the reloading store was going on and on about the lee factory crimp die. Is it worth picking up over some other die out there?

Now my .45 acp is another issue. I have found multiple rounds where I can easily push the bullet further into the case with just using my hand. I have been wondering if I have something set up askew or if applying a crimp will solve the problem.

sequoia_nomad
10-04-2011, 6:24 PM
A firm but sensible taper crimp is a good idea for semi-autos, as the transition from magazine into feed ramp into barrel can cause what is called "bullet setback", where the bullet is pushed down into the case, resulting in potentially catastrophic pressures.

When rsrocket1 speaks of neck tension, I believe that applies mainly to bottleneck rifle cartridges that will be shot in a bolt action rifle, since they will not be subject to the same forcible feeding as in an autoloader.

sequoia_nomad
10-04-2011, 6:30 PM
The only reason I bring it up is the guy at the reloading store was going on and on about the lee factory crimp die. Is it worth picking up over some other die out there?

Now my .45 acp is another issue. I have found multiple rounds where I can easily push the bullet further into the case with just using my hand. I have been wondering if I have something set up askew or if applying a crimp will solve the problem.

It sounds like you do indeed need to apply more crimp. You don't want the case mouth cutting into the bullet, just enough so you can't budge the bullet with firm thumb pressure.

As for the factory crimp die (fcd), myself and quite a few others believe it is an unnecessary gimmick marketed toward those who are uncomfortable setting up their dies. It does nothing that can't be accomplished by setting up your crimp die correctly. Many will argue that it's the best thing since sliced bread. Ymmv.

Sub95
10-04-2011, 6:52 PM
Now my .45 acp is another issue. I have found multiple rounds where I can easily push the bullet further into the case with just using my hand. I have been wondering if I have something set up askew or if applying a crimp will solve the problem.


are you using the same brand cases? or is it a mix of them?

if its a mix of different cases that will be the problem, not all case are the same and you will have to adjust your dies for that.

eridepilot
10-04-2011, 6:57 PM
are you using the same brand cases? or is it a mix of them?

if its a mix of different cases that will be the problem, not all case are the same and you will have to adjust your dies for that.

a mix of cases.

Sub95
10-04-2011, 10:56 PM
next time do one brand of cases and set the dies to that case and see how they come out.

there is a post about this with the 45acp somewhere in here.

GeoffLinder
10-04-2011, 11:25 PM
No crimp is needed for .223 or any similar rifle round IMHO. The case mouth and bullet are a solid interference fit if the size die and expander ball are doing their job properly. I do apply a slight taper crimp to my .223 ammo, but not for safety or feeding reliability, it is done to uniform bullet release tension. I find this reduces SD (standard deviation) over the chrono which results in slightly smaller group size at longer ranges (200-300+ yards)

rsrocket1
10-05-2011, 9:04 AM
A firm but sensible taper crimp is a good idea for semi-autos, as the transition from magazine into feed ramp into barrel can cause what is called "bullet setback", where the bullet is pushed down into the case, resulting in potentially catastrophic pressures.

When rsrocket1 speaks of neck tension, I believe that applies mainly to bottleneck rifle cartridges that will be shot in a bolt action rifle, since they will not be subject to the same forcible feeding as in an autoloader.

Actually, I mean only crimp with full house revolver rounds or bullets that are to be loaded in a tubular magazine. When loading 45 ACP, I use the Lee FCD on only to remove the bell that is put in when preparing the case to seat the bullet. I put no crimp on 45ACP, 40 S&W, .223, .308. I do put in a roll crimp on full loads of .357 magnum rounds.

You should have enough neck tension such that you can push the bullet as hard as you can with your thumb using hand strength only (not with the bullet against the table or wall) and it ought to stay exactly in place. 50 pounds of force on a 45ACP bullet is only 315 psi. The proper shot start pressure for a lead bullet is over 1100 psi and nearly double that for a jacketed bullet so you should be somewhere close to 200 pounds of force to move that seated bullet. That means if you can move a seated bullet by hand, you have too little neck tension.

Crimping to account for recoil:
I use an RCBS hammer type bullet remover and I know how hard I need to whack it to remove the bullets I load. For bullets to be pulled even part way using inertia only (the same thing we are trying to prevent when the bullets are sitting in a recoiling gun), you have to hit the puller pretty hard and more importantly, pretty sudden to unseat a bullet (at least you ought to). Most of these forces would be seen only on a really heavy revolver load.

Autoloaders pushing bullets into the case:
When I chamber a .223 in my AR, I see very little longitudinal force on the bullet as it goes up the ramp. Most of it if any, is lateral to the bullet. With no crimp, I typically see 15-20 fps in muzzle velocity differences using 25.0g H335 under a 55g fmjbt pill with a complete hodgepodge of mixed brass so I don't think I am seeing any bullet set back in my AR loads.

My opinion is that if you want to crimp, it doesn't hurt other than it wears out the case mouth a little more and if you are not careful, you'll mess up the bullet by crimping too much or you could cause a problem with cases that headspace on the case mouth. Just don't think that a crimp makes up for a loose fitting bullet. Fix that first.

Lead Waster
10-05-2011, 12:23 PM
It sounds like you do indeed need to apply more crimp. You don't want the case mouth cutting into the bullet, just enough so you can't budge the bullet with firm thumb pressure.

As for the factory crimp die (fcd), myself and quite a few others believe it is an unnecessary gimmick marketed toward those who are uncomfortable setting up their dies. It does nothing that can't be accomplished by setting up your crimp die correctly. Many will argue that it's the best thing since sliced bread. Ymmv.

I like to seat and crimp on different stages, so I use the FCD for that because ... why not? On a 550B, it makes no difference adding the extra die since without it, there would be an empty space in the toolhead (I don't have a powder check die)