If your adjusting the bullet seating die it is wrong to make it touch the shell plate. Only the Factory crimp die should be adjusted to the plate. The Factory crimp die is also a full length sizer and it could be swedging the plated Berry's bullet to a smaller diameter.
To help trouble shoot:
Remove the factory crimp die and use the bullet seating die as the taper crimp it was designed for. Place an empty shell case in the holder and raise the plate to the top position. Screw the bullet seating die in by hand until it touches the empty case. Then screw it in about 1/8 to a 1/4 turn and that just set your crimp. Tighten the lock nut and then adjust the bullet seater to the OAL you want.
This is the original way to crimp without using the full length sizer/factory crimp die. If this works for you then maybe the plated bullets should not be used with the full length sizer/factory crimp die.
I love the 38/357 factory crimp die when using Lead bullets and Jacketed bullets
BUT you should not adjust you bullet seating die to crimp it first and then put it through a second crimp cycle. A double crimp does not work well.
To help a lot of misconceptions the dies should be labeled as follows:
- Bullet Seating and Taper Crimp Die
- Factory Crimp and Full Length Sizer Die
Both dies crimp and it would help if Lee labeled them as such.
Here are cut and paste from their web site FAQ's
Factory crimp die adjustment
The amount of crimp applied will be consistent if your press has mechanical stops built into the lever linkage, and you lower the lever to the stop every time. Start with the Factory Crimp die turned into the press until it stops against the shell holder with the ram raised all the way. Lower the ram, and turn the die in one full turn. Now try crimping a case, making sure that you raise the ram (lower the lever) all the way to the stop. You will feel slight resistance at the top of the stroke, as the crimp collet is forced up into the die body.
If the crimp is not firm enough, turn the die in another 1/4 turn and try again. If you turn the die in to the point where the four slits in the collet are closed when the ram is raised all the way, you have reached the limit.
Bullet Seating Adjustment
The trick is to set the bullet seating depth first,
then the crimp. This is done as follows; With an empty, sized case in the shell holder, hold the ram at the top of its stroke. Turn the bullet seating die body down over the case until you feel it come to a stop. This will be when the case mouth contacts the crimp shoulder inside the die. Mark this position by turning the lock ring down against the turret or press frame. Now adjust your bullet seating depth. Once you have the bullet seated to the desired depth, back the bullet seater adjuster out about 1 turn. Now turn the bullet seating die body in to apply the desired crimp. Once this is established, hold the ram at the top of its stroke and spin the bullet seater adjuster down until it stops.
It is a good idea to carry this out with an empty case, so that after you have seated the bullet, you have a perfectly safe "dummy" cartridge (or gauge) to repetitively set seating depth and crimp on future occasions.
Once you have this "dummy" gauge, all you have to do is place it in the shell holder, raise the ram to the top of its stroke, turn the bullet seating body down until it stops, and then turn the bullet seating depth adjuster in until it stops. Since the crimp and the seating depth were already set, the die will return to very close to the same settings.
What they do not tell you is to back off the seating crimp if you are using a Factory crimp.
Hope this helps.
