Originally Posted by statjunk
On the advice of many here I decided to give bumping a try as opposed to simply neck sizing. To say that my first attempt did not go well is an understatement. I'm hoping that by describing what occurred that someone can offer me advice.
Here goes. I first took the fire formed brass and I measured it using the RCBS precision mic. The measures varied somewhat but I settled on .002 larger than Sammi. I chose to bump the shoulder .002 so that would essentially mean that I need to bump the shoulder into Saami spec. Zero on the gauge.
I then put the brass in the press and sent the ram to the top. Then I started to thread the FL sizer die down onto the cartridge until it stopped. At this point the die is sticking out of the press like 1/2 - 5/8". This is from a normal position where I would FL size when business as usual. I lowered the ram and dialed the die down a half turn. Lubed the case and sent it up into the die. It met very little resistance pulled it out and miced it. The measure didn't change. Turned the die down a little more, send in the brass, mic again. No change. Did this a couple more times. Nothing. Sent another fire formed brass into the die and it came out .004 under saami spec. Dialed the die out a bit and tried it again. Nothing.
I went through several pieces of brass trying this before giving up and deciding to write a post here. I had a buddy with me and he was as confused as I was.
Any ideas what I did wrong?
Back up inf0: remington brass, Lee dies, Lyman press
I'm Not sure that you did anything wrong you may have a set of dies that won't let you bump
the shoulder. (Some dies are adjusted by seating the die against the shell holder).
I switched to dies that don't seat against the shell holder so I could fully adjust to what case
size I wanted. I like the new dimension dies from Hornady because you can adjust down to
a small base setting (Normally .003 to .004 smaller than SAAMI Spec.)
There have been a lot of good suggestions and I would add that I always anneal before I
bump the shoulder to minimize spring back.
Also I remove the expander ball during the setup and just keep turning the die down untill
I get the desired size(One case) and then try a new case to check if it needs tweaking then
replace the expander ball/plug and proceed.
As BB said I never bump the shoulder unless it is nessary and always anneal befor I start.
Hope this helps.
J E CUSTOM