Different 45 ACP Taper Crimp Dies

For some reason or another which was probably pure boredom I changed my crimp dies out.
I have a RCBS and a Dillon taper crimp die. 
I had some leftover ammo from a previous match that I decided to pull which were jacketed bullets These had been crimped using the Dillon tapered crimp die and the die was set at .469".
I was using jacketed bullets because I was shooting in an out of state match and didn't want to have to clean lead out of my barrel since the new batch of Zero LSWHP bullets like to lead the barrel throat of my pistol. (I'm still waiting for a response from Zero that was sent months ago on the poor QC for this product)
I noticed that the pulled jacketed bullets looked to have a groove where they had been crimped so I pulled the die and started comparing it to the RCBS die.
The RCBS die has a long tapper crimping surface where the Dillon is short and abrupt which causes the edge of the case mouth to dig into the bullet similar to a roll crimp but not as pronounced.
The RCBS leaves a slight ledge but no groove. 
The tighter you set the Dillon die the more pronounced the groove becomes, the RCBS can't be set tighter than .465" where the Dillon will crimp to .463" and tighter.

Now for the 64,000-dollar question, is the Dillon a roll crimp or tapered crimp?

Greetings,

One way is to make a chamber cast of the die and look at it with a magnifying glass or Optical Comparator.

I wrote to RCBS years ago asking what the taper angle was. The reply was 4 degrees per side.

This is the angle I used to machine Taper Crimp dies.

Cheers,

Dave

fc60 wrote:Greetings,

One way is to make a chamber cast of the die and look at it with a magnifying glass or Optical Comparator.

I wrote to RCBS years ago asking what the taper angle was. The reply was 4 degrees per side.

This is the angle I used to machine Taper Crimp dies.

Cheers,

Dave

Thanks for the response Dave.
The Dillon die has a sleeve that incorporates the taper crimp in the die. Maybe I can set it to crimp a lead bullet at .463" so you can see the groove left in a bullet.

The RCBS will be more consistent with crimp diameter with varying case length than the Dillon due to the shallower crimp angle.

I grabbed a couple of 200gr 130 H&G bullets I cast and a piece of brass to try and get some pictures of the crimp marks on the bullets from each die.
Each bullet was loaded in the same case which was sized and the case mouth belled for each bullet.

Not all the pictures uploaded so here is the fourth one.
The dies were set to crimp at .463"
The picture here is of the bullet crimped using the Dillon die and you can see how it deformed the bullet.
the two bullets were unsized and .453" OD, the bullet from the Dillon crimp OD measured from the top was .450", the crimp groove .445"and the base was .452".   
The bullet crimped by the RCBS die was more uniform, the top ring OD was .453", the crimp grove .445", the bottom ring was .453".
In the other post it isn't hard to pick out which picture is of the Dillon die or the RCBS die.
If you want a light crimp the Dillon die will do that and not deform the bullet but for a tight crimp the RCBS die is the way to go.
The RCBS die set for max crimp

You really should check out the LEE factory crimp die. Works like a charm!

Fotomaniac wrote:You really should check out the LEE factory crimp die. Works like a charm!

Thanks for the response. I'm trying to use what I have on hand and really don't want to invest in more equipment since like everyone here I already have a sizable investment.

Seriously?! They are like $28 or so. LEE dies are not shabby, and not overpriced. But, it’s your call.

Fotomaniac wrote:Seriously?! They are like $28 or so. LEE dies are not shabby, and not overpriced. But, it’s your call.

Thanks for the response, maybe I will after I see how another project works out. Got plenty of time till next season when the matches restart.