I was given a Lyman taper crimp die for 9mm. No instructions, and I can't find anything about a Lyman die. It is not a seater die also. Just a taper crimp. Can someone explain to me or send me somewhere I can find out how to use this.
ACC
Printable View
I was given a Lyman taper crimp die for 9mm. No instructions, and I can't find anything about a Lyman die. It is not a seater die also. Just a taper crimp. Can someone explain to me or send me somewhere I can find out how to use this.
ACC
The easy answer is to phone Lyman and ask them. Most crimp dies, be they taper or roll, require you to raise the ram and shell holder all the way, then turn the die in 1/2 to a full turn more to achieve the crimp. Might be that you'll only need to screw it in to contact and no deeper, since the die is made only to crimp. 9mm brass is plentiful, so you can afford to experiment a bit until you find "the spot".
I raise the ram with a loaded case.
Turn the die down until it 'hits'.
Lower it, turn the die in 1/2 turn or less, raise, repeat until you can feel the 'bell' on the case mouth has rolled back in.
You'll feel a 'bump', but remember, you're not trying to resize the boolit.
Test fit/plunk it in a case measuring tool or pistol chamber.
The loaded- or dummy round will tell you when it fits right.
They tend to be forgiving, but I check a few before I go into mass production.
The common seating die in a set puts a roll crimp on the mouth of the case. With calibers that headspace on the case mouth a roll crimp is not desirable as the headspace changes with the amount of roll crimp. Also a roll crimp digs into the bullet as theroll crimp is applied while the bullet is still being seated. Most people that taper crimp do not apply any crimp while the bullet is being seated and taper crimp in a separate step. The taper crimp die is screwed down where the case hits the die when the ram is all the way up. As you apply more taper crimp( screw the die down) the mouth of the case gets smaller. There is usually an ideal diameter that is desirable for your caliber.
I have several of the Lyman taper crimp dies and seat only with the seater/crimp die and then use the Lyman taper crimp die to apply a taper crimp for the rimless cartridges. The taper produces a true taper crimp and not a modified roll crimp that a standard "taper crimp" die produces because they taper they have is so short. Because the taper is longer it is easy to over do it, so as suggested, screw the die down until you feel a slight resistance, check the case mouth and adjust down until you get the crimp you want.
I tend to agree with the half turn rule of thumb. Hasn't let me down yet!
For me it depends on type of cartridge, revolver or semi-auto. I started adjusting revolver crimping waaaay back by inserting a case, raising it up into the die and screw the die down until I felt it touch the case then used the "+ 1/2 turn" method, (which I soon lowered to 1/8th to 1/4) and that was a fairly good starting point. I used an empty case so I could see how much the case mouth was turned in (yeah, I know it will be slightly less when a bullet is in place). Then crimped a few loaded rounds to tweek the crimp. I often had to back off the die from the half turn to get the crimp I wanted for a specific round. For my semi-autos I run the case up, screw in the die until it touches the case then lower the die about 1/8 turn. Then I'll run a few loaded rounds through and plunk test them (I don't crimp semi-auto rounds, I just "deflare" them). I crimp 5 revolver cartridges and 4 semi-auto cartridges this way and I rarely have an problems resulting from poor crimping...
Ed gave ya good instruction!
My fav cast bullet crimp as I can go light to firm and at least in my mind it’s less “offensiveL toward the bullet.
I like Redding TC dies my self. Just bought another last week in 32 Long for use with my 327 Fed Magnum.
Attachment 255062
CW
That’s my MO as well.Quote:
Originally Posted by mdi
It is way easier to turn a crimp die in small additional increments than to reverse to heavy of a crimp.
After I have reset a crimper about so many times I get a fresh uncrimped cartridge and finish my adjustments with that one or even a third round if necessary because the casing mouth only takes so much futzing with. You need to have the die set properly for a “one off” operation, not one that has been through the wringer.
Best regards
Three44s