Trouble getting consistent shoulder setback.

The 550 will flex for certain with big cases. A custom ammo maker i know wont use Dillons with the interchangeable heads, he buys every 450 he can find though.
I had the same issues with the Lyman, which is actually what made me try the Dillon. I'm leaning towards the advice about the cam over clearance. First, I'll try going back to the Lyman, and taking a few thousandths off the top of the shell holder. If that solves the problem, I'll consider buzzing the bottom of the die down a couple thousandths.

Using the Dillon for brass prep is just too dang convenient to abandon if I can avoid it, and I've had good success in other calibers. It's plausible that my headspace on the 300WM is relatively short for the dies, as I installed the Shilen barrel with as little I could get away with. The Shilen leaves the shoulder 0.002" - 0.006" shorter on fired brass compared to the old barrel and a couple of buddies' rifles.
 
I had the same issues with the Lyman, which is actually what made me try the Dillon. I'm leaning towards the advice about the cam over clearance. First, I'll try going back to the Lyman, and taking a few thousandths off the top of the shell holder. If that solves the problem, I'll consider buzzing the bottom of the die down a couple thousandths.

Using the Dillon for brass prep is just too dang convenient to abandon if I can avoid it, and I've had good success in other calibers. It's plausible that my headspace on the 300WM is relatively short for the dies, as I installed the Shilen barrel with as little I could get away with. The Shilen leaves the shoulder 0.002" - 0.006" shorter on fired brass compared to the old barrel and a couple of buddies' rifles.
I have had great success getting consistency by using Imperial sizing wax and either of my Co-Ax presses. I an setting back .002" and annealing every 4 firings. Eagleye
 
body die , bottomed out on redding competition shell holders , with press cam over

you can put feeler gauges between the shell holder and dies to accomplish the same thing , as long as you can bottom it out and not over size

comp shell holders#6 https://www.midwayusa.com/product/1012456684

ya they are 50 bucks but the#6 can be used for your 300 win & all of the following

  • 223 WSSM
  • 6mm-300 WSM
  • 25-300 WSM
  • 25-300 Remington Ultra Magnum
  • 257 Weatherby Magnum
  • 257 STW
  • 264 Winchester Magnum
  • 6.5mm Remington Magnum
  • 6.5mm STW
  • 6.5mm-300 WSM
  • 6.5mm-300 Weatherby Magnum
  • 6.5mm-300 Remington Ultra Magnum
  • 270 Weatherby Magnum
  • 270 WSM
  • 270-300 Winchester Magnum
  • 270-300 Weatherby
  • 270-300 Remington Ultra Magnum
  • 284 Baer
  • 7mm Remington Magnum
  • 7mm Remington SAUM
  • 7mm WSM
  • 7mm Weatherby Magnum
  • 7mm Hart Magnum
  • 7mm Remington Ultra Magnum
  • 7mm STW
  • 7x61mm Sharpe & Hart
  • 7x66mm Vom Hofe S.E.
  • 7mm- 300 Weatherby Magnum
  • 7mm-300 Winchester Magnum
  • 7mm-300 Remington Ultra Magnum
  • 7mm-350 Remington Magnum
  • 30 Hart Magnum
  • 30-338 Winchester Magnum
  • 30-8mm Remington Magnum
  • 30-350 Remington Magnum
  • 300 H&H Magnum
  • 300 Winchester Magnum
  • 300 Weatherby Magnum
  • 300 Mashburn Magnum
  • 300 Jarrett
  • 300 Remington SAUM
  • 300 Remington Ultra Magnum
  • 300 WSM
  • 308 Baer
  • 308 Norma Magnum
  • 8mm Remington Magnum
  • 8mm-338 Winchester Magnum
  • 8mm-300 Winchester Magnum
  • 8mm-300 WSM
  • 8x56mm Mannlicher
  • 338 Winchester Magnum
  • 338 Baer
  • 338 Jarrett
  • 338-308 Norma Magnum
  • 338-300 WSM
  • 338-8mm Remington Magnum
  • 338-300 Winchester Magnum
  • 338-350 Remington Magnum
  • 340 Weatherby Magnum
  • 338 Remington Ultra Magnum
  • 35-8mm Remington Magnum
  • 35-338 Winchester Magnum
  • 35-300 Weatherby Magnum
  • 35-300 WSM
  • 350 Remington Magnum
  • 358 Norma Magnum
  • 358 STA
  • 9.3x74mm R
  • 9.3mm Wilson
  • 375 H&H Magnum
  • 375 Mashburn Magnum
  • 375 Weatherby Magnum
  • 375-300 Winchester Magnum
  • 375-300 WSM
  • 375 Remington Ultra Magnum
  • 375-8mm Remington Magnum
  • 375-338 Winchester Magnum
  • 375-350 Remington Magnum
  • 416 Remington Magnum
  • 416-300 Remington Ultra Magnum
  • 416-300 WSM
  • 416 Hoffman
  • 416 Taylor
  • 416 Express
  • 425 Express
  • 450 Ackley Magnum
  • 450 Marlin
  • 455 Webley
  • 458x2" American
  • 458 Winchester Magnum
  • 470 Capstick
 
I have also had good results using the appropriate feeler gauge under the case with Forster CoAx press & neck/shoulder bump dies.
 
I have had the same problem.
If you have any space between the shell holder and the die, you don't need the Redding shell holders - they add to the problem if you are having trouble bumping shoulders back enough. If you are camming over (which is good for consistancy) then two things might be happening. First is that you are getting inconsistent springback of the brass and you need to anneal your brass. Second is the die and shell holder combination is not letting you push the shoulder back far enough which is cured by grinding the die or shell holder a bit. Remember to keep that shell holder dedicated to that set of dies.
The first solution is easy with a torch and drill method of annealing. The second is a judgment call and remembering that shell holders are cheaper than dies so grind the shell holder before you wreck a good set of dies.
Letting the press dwell at the top of the stroke can help with consistency but this works better if the cases are newly annealed.
 
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I have used some huge presses in the past thinking this was necessary to get the desired outcome.
Came to realise that my 60's era Rockchucker was sufficient, but soon moved to the Rockchucker Supreme due to case lengths I had moved into, Gibbs and Rigby based cartridges are LOOOONG.
CAM OVER is key, it controls bump to .001" springback consistently and hovering, doubling or rotating the case often helps too.

My Redding Big Boss II gathers dust now, never use it.

Cheers.
I've always use a Wilson FL size and back it off after touching the shell holder then try it in the chamber and move down until it works in my rifle !
 
One thing I forgot to mention, how consistent is your measurement? If you measure the same case 10 times, how many different measurements do you get? If you don't get near 5 same measurements your technique may need some work.
 
One thing I forgot to mention, how consistent is your measurement? If you measure the same case 10 times, how many different measurements do you get? If you don't get near 5 same measurements your technique may need some work.

I've measured many many fired cases, and always get the same number ± 0.0005 (all my caliper is capable of).
 
Anneal and use enough lube. I was having problems with the Imperial and went back to RCBS lube and pad and now all good. If the case doesn't go in to the die smoothly and come out smoothly, you're going to get variations. If it makes any noise going in or out, that's chatter and it will vary the setback. Even if it takes a lot of pressure it needs to be smooth. Also sorting cases by how many times they have been fired and loaded will help with the consistency.
I use a Wilson F/L bushing die without the bushing for sizing the case and a Lee Collet Die to size the necks. The expander ball coming out of the neck can stretch the case or pull the shoulder out and give varying measurements.
 
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When setting up a die you don't want to btm out on your shell holder before the press stroke is complete. This will overstress your press and break things. You shouldn't have to overcam to size correctly.
There are presses designed to cam-over, and there are presses that are not.
When setting up a die in a press WITH cam-over ability, it is IMPORTANT to use the cam-over function, even slightly, because the slop in the linkage WILL give inconsistent springback.
The reason is due to differing resistance from brass case to brass case. Resulting in anywhere from .002"-.008" difference in headspace measurement after sizing.
I no longer neck size with bushings, I use honed neck Forster FL dies with custom sized/polished expander and bump EVERY case for .001"-.0015" head clearance.
The only way this is consistent is with cam-over.

Cheers.
 
Yp
I've always use a Wilson FL size and back it off after touching the shell holder then try it in the chamber and move down until it works in my rifle !
You should be starting with the die out enough to not bump the shoulder. Then screw the die in a little at a time until you get the desired shoulder bump. Too much shoulder bump in a loose chamber will result in case head separations and potentially missing fingers and eyes
 
Yp

You should be starting with the die out enough to not bump the shoulder. Then screw the die in a little at a time until you get the desired shoulder bump. Too much shoulder bump in a loose chamber will result in case head separations and potentially missing fingers and eyes
A case head split rarely results in firearm damage, let alone damage to the shooter.
It actually occurs at the end of the cartridge/chamber burn when near completion. Just prior to bullet release, this is evidenced by little sooting on the case or chamber after such an event.

Cheers.
 
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