Shoulder bumping question.

[clrems77]

Bought myself a shoulder bump gauge and need some help setting up the die. First of all, do I need a special die or can I use my Redding or Forster FL dies? If I can use my dies, how do I go about setting them up to bump back?

Thanks!

CJ

 

[memo43]

Any die that is a full length size will work. Bump gauges measure directly of the shoulder datum line.
measure your fired cases using the new tool, note measurement an install your F/L die accordingly, just dont seat it all the way down.
start sizing a case an measure an take measurements to see if the die has made contact.
if not keep running the die down a bit until you have made contact. once you have made contact constantly your measurements, until you have achived the amount of set back yu want. Setting up the die the first time is a real pain, but once you get the hang of it, its goes by quick.

 

[fw707]

Good info there.
Blacking up the neck of the case with a Sharpie makes it easier to check your progress.
I use Forster FL dies.

 

[Assault116]

Also, one thing you might notice, as you start getting close the case may actually grow in length ie instead of bumping back, you'll see a longer measurement, then once you make contact with the shoulder, it will start getting shorter. For a bolt gun, I'd look for a bump back of .001-.002" and for a semi-auto, the rule of thumb seems to be .003"-.005".

Keep in mind during setup that 1 full turn of the die equates to about .071" in depth into the press (14 threads per inch on the die) so you're going to be making VERY small adjustments to your die depth. I highly recommend that you use a locking die ring of some sort, like Hornady or Forster rings, even RCBS and Redding lock rings have a set screw to lock them in place. Use it and it will make setup the next time a bit easier. The only ones I've used that don't have some sort of locking mechanism is Dillon. Not sure about lee or lyman, never used them.

 

[bax]

If you are using them in a single-stage press you can put set screw lock rings on your Dillon dies. I bought a Dillon carbide in 308, put on a lock ring with a set screw. I use it in an A2 and it is right every time. If you want to use them in a 550 or similar, you might be able to turn down a ring with a set screw - there isn't much force there so you don't need much metal.