roll crimp vs. taper crimp

[whitedogone]

What's the difference? I am loading the 44 mag with RCBS dies.
I am thinking of adding the Lee factory crimp to the mix. What is the difference is the lee one type and the 3rd die of my die set something else?

[mr-geep]

A roll crimp actually pushes the edge of the casing into the bullet, holding it in place. This is usually needed on high power revolvers to keep the bullet from being moved by recoil and keeping a revolver from indexing.
A taper crimp "tapers" the casing, holding the bullet in place, not as strong a hold on the bullet, but some cartridges headspace on the end of the casing so you cant roll crimp it, which would shorten the cartridge.

[Doodlebugger45]

You want a roll crimp with your 44 mag. Light loads only need a light roll and heavy loads need a firmer roll crimp. The 3rd die in your set is the seating die. If you adjust it correctly, you can make it do anything from a light roll crimp to a heavy roll crimp, but it's kind of a tricky thing to seat and crimp in the same step. At least at first it's tricky until you get the hang of it. The Lee FCD makes doing the crimp even easier. Basically, you use the seater die just to seat the bullet to the right depth. Then you come in with the FCD and apply a perfect crimp just the way you want.

Taper crimps are mainly for auto cartridges where you don't have a cannelure to crimp in. They basically just add a bit more neck tension to the bullet. That is necessary because most autoloaders headspace on the neck of the case, so you can't have it rolled into the crimping groove.

[whitedogone]

thanks ..... i've been just trying to seat a few dummy rounds to play with the seating/crimp die. It just doesn't seem right to be crimping while still seating the bullet.

[res45]

You can try this,adjust your seating die up so it's just a few turns off not crimping and lock it down,adjust the seater plug down till you get the bullet in the position you want it in on the cannelure or crimp groove of the cast bullet your using.

Now take the seater plug out or back it way off,adjust the seater die body down a little at a time till you get the desired crimp then lock it down with the allen screw. Run the rd. up into the die with it applying the crimp and adjust the seater plug till it touches the bullet snugly and lock the seater plug in place. Load a rd. and see if it's seating the bullet and crimping it like you want you can make minor adjustment up or down on the seater plug if necessary.

[whitedogone]

thanks res45,

I guess I'm not sure what I am looking for in the crimps/bullet depth.

[Doodlebugger45]

You're pretty close I would say. It's kind of hard to tell from pictures for me though. Besides the "look", I sort of rely on the "feel" somewhat. And yes,. everybody has a different idea as to what is a "light roll crimp" vs a "heavy roll crimp". You are close but if I can see it clearly enough, I would say your crimp might be a bit too heavy and the seating depth a tiny bit too shallow. Was this done with or without the Factory Crimp Die? You are close though. If it was done WITH the factory Crimp Die, then I would leave the seating die alone for now and just back off the FCD about 1/4 or 1/2 turn and see what that does. If it was done without the FCD, then I would leave the seating die as is for one round, but back off the entire die about 1/8 to 1/4 turn and see what it looks like.

For me, the best model I had to use was a factory round. I figured Federal or Winchester or Hornady knew what a proper roll crimp should look like for a 44 mag, so I just experimented until I had the top of the brass crimping into the top of the crimp groove and the roll crimp looking about like the factory round.

[warnerwh]

Many people seat with one die and crimp with another. I know Lee makes 4 die sets. I happen to have a Lee set and an RCBS set for both the .357 and .44 rounds because I needed the longer RCBS dies for a Dillon press I had in another life. Ask Lee if they will sell you a roll crimp die. I think doing the seating and crimping separately is the best way to do it. The manufacturers do to.
I think a roll crimp die would be a good idea for you to have.

[res45]

This is my 158 gr. cast bullet load crimp,I use a Lyman three die set I've had for over 25 years. I seat and crimp all my pistol ammo in one step,I like the Lee FCD that came with my rifle dies but I have none for my pistols.

It appears from what I can see is your bullet is just a little to deep or that your case mouth is a bit out of round,its going under the bullet on the right side and almost overlapping the short driving band on the left side. It should look like this,you may want to trim one and see if it trues up the case mouth.

[Doodlebugger45]

That is a beautiful roll crimp. I would call that a heavy roll. Perfect for hot loads. Some bullets and cases are easier to get such good definition on them. Some people prefer a lighter roll to preserve brass life, but I like the looks of crimps like that for my heavy loads.

[whitedogone]

Well, I tryed to get a better pic. It was shot next to a WW factory round. Why does it look canted? Is the groove on the bullet not square with the world, or my die, or something else?

[MADISON]

...and I'll say it again:
I have been TAPER CRIMPING ever caliber I reload for for 25 years.

All you have to do to try it is to remove the decapping stim from your sizing die and readjust it for crimping.

[res45]

Well the WW factory rd. has only been loaded one time and never fired,from the looks of the cannelure on the cast bullet load it has at least been fired once? Your loaded case has been subjected to being fired,resized,belled and crimped so naturally the brass has been stretched and manipulated somewhat,how much depend on how it was loaded and the pressure put on it when fired all chambers swell and stretch brass differently. You also have to take into account your cast bullet is .01 or .02 larger in dia. than the jacketed bullet so it works the case a bit more when loading and also affect seating.

I think you need to trim a few case and back off the crimp just a bit more,I don't use Lee FCD's on pistol ammo I'm just assuming it puts a crimp on the case similar to the WW factory rds. pictured. Maybe someone can post some pics of the type crimp it puts on cast and jacketed bullets on revolver cases,I can't seem to find any.

If you case mouth is not flush across the top you will get that canted look around the crimp area,on jacketed bullets it's not a problem because of the wide cannelure but on a cast bullet with a defined crimp area it's just going to be more noticeable when one case is long and the next is short and the next is in between length wise,your bullet is most likely going to seat at the same depth or close each time. But crimp is going to start folding over when the brass touches the built in roll crimp if the case is long the crimp will be higher on the bullet if the case is short it will be lower.

Thats why I trim on occasion and keep my revolver cast load cases separate from the jacketed stuff so I have better control over the case length and crimp and seating the bullet the same each time.

[whitedogone]

Backed out the entire seating/crimp die 1/4 turn. It's the middle one.

[Doodlebugger45]

That'll work! Looks good although it's probably more crimp than you really need. No problem though, it will still shoot great. The only problem with applying a heavier crimp than necessary is that it works the brass more and the brass won't last as long. It's a good tight roll crimp though. If it was me and I wasn't shooting a real bruiser like a full house 454, I might back off the body of the die just slightly, maybe an 1/8 turn at a time while screwing in the seating plug about an 1/8 of a turn in order to preserve the same total overall length while crimping a bit less.

[res45]

+1 on what Doodlebugger45 said,looking good.

[whitedogone]

Thanks guys, Does the "divit-ring" that the seating die left hurt anything?

[whitedogone]

Going to try and load up 20 or so for the weekend. These are light loads. 200gr nad going with universal. Manual says starting@ 6.8 for 897 fps and max@ 7.8 for 1045fps. I was thinking of loading them at 7.2 grains.

[teeroux]

I've found roll crimps will fall into the chambers on a cylinder better than a taper crimp

[alloy]

Thanks guys, Does the "divit-ring" that the seating die left hurt anything?

Probobly only hurts your brass life, but if you keep pushing it thru the die until that ring shows or until the ring gets longer, you are really only getting some type of modified taper crimp. Reaches a point where it just keeps going thru the die anf flattens out(your divot ring). I back mine out when until I see that ring disappear, and figure thats the max roll crimp I will get for that bullet/die combo. A few of my dies just don't roll very good, for those cartidges I use a Redding profile crimp, but that last pic, middle round, looks nice...

[res45]

I has some time to kill last night so I took 50 pieces of brass I use in my heavy cast bullet loads that have about five firing on them,I used my Lee trimmer setup in the cordless drill and ran ever case through and every one was cut back to various degrees.

Some brands of cases stretch more than others so be aware of that if you shoot mixed brass if you start getting bullet seating depths varying a lot. Also whitedogone if your new to shooting cast bullets it's a good idea to take your die apart ever so often and clean it out,the lube on cast bullets can build up inside the die body and on the seater plug and start causing problems with the crimp and bullet seating depth on occasions.

On load development for a handgun with a spread of only 1 gr. from min. to max charge I usually just load up six rds. in .2 tenths increments starting with the min. charge and stopping at .2 tenths off the max. and shoot a target with each load separately off a rest. You can also color each bullet tip around the ogive with a different color sharpie and it will leave a colored ring for that bullet on the target if you happen to be shooting at a range that you cant change out your target till everyone is done shooting.

Once I find the load that shoots most accurately I duplicate that load again and see if I obtain the same results if so thats the load I go with,all the MV in the word doesn't do you any good it you can't hit what you aiming at. One thing of note if you shoot a lot of copper jacketed bullets in your pistol or rifle it's a good idea to clean your bore before shooting cast bullets in it,copper fouling acts like and abrasive and strips the lead off your bullet as it passes through the bore.

[Sarge]

Post #5 by res45 is the perfect illustration of the perfect roll crimp, as applied to lead bullets in revolver cartridges.

Fine work, res45. I would like to borrow that image from time to time to time for illustration purposes, if you have no objection.

[res45]

NP Sarge use it all you like

[whitedogone]

"Quote:
Thanks guys, Does the "divit-ring" that the seating die left hurt anything?

Probobly only hurts your brass life, but if you keep pushing it thru the die until that ring shows or until the ring gets longer, you are really only getting some type of modified taper crimp. Reaches a point where it just keeps going thru the die anf flattens out(your divot ring). I back mine out when until I see that ring disappear, and figure thats the max roll crimp I will get for that bullet/die combo. A few of my dies just don't roll very good, for those cartidges I use a Redding profile crimp, but that last pic, middle round, looks nice... "

I was refering to the "divit" in the lead itself....up on the ogee

[res45]

Does the "divit-ring" that the seating die left hurt anything?

Thats pretty minor compared to some I've had and have seen it want cause you any problems,it's generally cause by the bullets ogive not fitting to the shape of seater plug,those plug are pretty generic and often times on new ones there also pretty sharp on the inside edges. Also the lead bullet is softer and being slightly oversized requires a bit more pressure to seat it in place so hence the divit.

With some bullets you want get that at all with some you will. You can try your other seater plug if you die set came with more than one,my Lyman dies had three and my RCBS dies have two. you can also take a jacketed bullet put some valve grinding compound in the plug and use it to polish the inside edges of the seater plug or use a dermal tool with a buffing wheel and do the same thing just take it slow.