Trouble with Lee 357 seating die

[MT Chambers]

This is the first time that I have heard of problems with Lee dies.

[44man]

This is the first time that I have heard of problems with Lee dies.

I can look at groups and tell you what primer you used and am close to telling you what dies you used.
Might sound crazy but what you do to brass counts more then anything. Look back and see how many times I said "brass is your enemy." if you see me with an "M" die or FCD, you know I lost my mind. Getting close enough at my age anyway.

[theMickster]

So the plot thickens.....
I contacted Lee through their customer service Web page yesterday. Today I received an email shipping notification from Lee.... for a decapping mandrel. WTH? Whatever!
Got the RCBS 357CBY set in today's mail. I proceeded to measure the seat die 's mouth. It is .386 and worked fine to seat and roll crimp my cases. I'll report back with accuracy and hopefully no leading.
I did notice the RCBS CBY expander is stamped .358. It measures out at .356. Lyman M measured at .357. I decided to make one myself a little more appropriate for fat cast boolits. .359. I'll try it out next time I load.

Mick

[theMickster]

I loaded 50 rounds with the new RCBS CBY dies. I used unsized, brand new Starline brass.
Lyman 357446 sized .3595.
Red Dot from 3.1 up to 4.7.
Accuracy was terrible at 25 yards. Perhaps I am not a good pistol shot off of a sand bag......
The good news is the leading was only light in the throats. None in the barrel!
This is a step forward.
A couple observations:
1. Unsized brass when loaded the way I did it is a slip fit into the cylinder. Cartridges hardly rattled at all.
2. A pulled bullet was only slightly under sized diameter. .358+

Mick

[462]

You say the new RCBS seating die swaged the boolits from .3595" to .358". Is that something you want? Do you suppose that may have attributed to the "terrible" accuracy and the "light" leading? Just asking, as none of my seating dies act as swagers, too.

[theMickster]

I can't really attest to the accuracy of my measurements this afternon. I will recheck when I get home from work. That's what I thought I saw. I was multitasking and may not have paid attention to what I was doing. I will make a more scientific test side by side with the Lee dies and measure before and after. I think my point was more to the fact that progress was made.