elkaholic
Well-Known Member
Did you check from there and see if less than .005" will work? Do you have Whidden bushing or Forster STD dies?
My 338 Sherman Shortmag
- Thread starter ruby76
- Start date
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ramrod79
Well-Known Member
Hey Rich no I was waiting to see what anyone else was getting. They are Whidden dies as well. Like I say brass will cycle but snug. Right now I have 5 brass sized from 1-7 thou they all cycle just snug and I usually run a bit tight but not like this.
elkaholic
Well-Known Member
I haven't heard this yet from others, but here is a theory. The bushing dies normally don't push the last .020" of the shoulder and with necking the 7mm up to 338, there is potential for brass thickening at the shoulder/neck junction. It COULD be that it is head spacing on that small area? Try marking your cases and see if you see any witness marks?
ramrod79
Well-Known Member
If I run die up so I'm just neck sizing then they are fine too I did a few this way. So I think for first round of development I'll just neck size them and shoot see how they hold up.Brass length is 1.935 long shot
ruby76
Well-Known Member
It took me a bit of playing around to set up the die correctly for the proper shoulder bump. As well I found that at first I didn't have the bushing seated down far enough and wasn't fully sizing the neck.
ramrod79
Well-Known Member
I'm not sure how you mean to mark cases for witness marks.
elkaholic
Well-Known Member
Your chamber is 1.940" so the length is perfect.
elkaholic
Well-Known Member
Just draw a couple limes with a marker down the full shoulder length on to the neck and close your bolt a couple times and then read the case
bigngreen
Well-Known Member
I find if I'm struggling with hitting the shoulder bump it's an indicator annealing is needed.
ramrod79
Well-Known Member
Yea you shouldn't have to play with dies like this half turn off ram should not push shoulder back 7 tho. I'm 2.5 full turns off ram to fully neck size and get a good fit.
ramrod79
Well-Known Member
Shouldn't need to anneal they came annealed fired once I could give it a go thou.
ramrod79
Well-Known Member
Rich I have marked the ones with7 tho bump the ones that are neck sized and the ones that are bumped 1-2 tho..
So the ones that are bumped 2 tho have small wear in lines on shoulder after 20 cycles.
The neck sized ones have no marks in lines after 20
And the ones that are 7 thou have no marks in paint.
elkaholic
Well-Known Member
So it sounds like full length sizing MIGHT be pushing material around that base of the neck area? For now, it would just bump it back a thou at a time until it is closing. You might try turning the doughnut out if you have a 40 degree cutter and just kiss the shoulder. If it then closes well with .002" bump, that was the problem .Some guys ream the bottom of the bushing stop out of the die about .020" and then the bushing pushes the entire shoulder.
ramrod79
Well-Known Member
Unfortunately I don't have a 40 deg cutter never needed one. I did anneal brass again like BG suggested and I am able to get a 2 tho bump that closes relatively decent. I'm not sure how this will affect my accuracy through out load development or how brass will be to size next go around or if this problem will keep plaguing me.
If I have to start reaming dies or doing all sorts of brass work that will be a show stopper.
If I have to start reaming dies or doing all sorts of brass work that will be a show stopper.
