Bump sizing

[ctafoya]

So I have been out in the garage scratching my head for the last hour and watching you tube videos. I can't seem to get how to bump size. I'm using RSBS full length die set. No matter what I do I cant get the shoulder bumped back. Any help would be greatly appreciated.

[Big or Bust]

Turn the die down more. Then keep trying to chamber. When it does, lock it in place. Keep sizing. I check about every 10th one....

[ctafoya]

Done that. I keep measuring and no change. I just read that rcbs dies can't do this?

[cjl2010]

Do you do it till it chambers or is it supposed to be .001-.002?

[muledeerarea33?]

The body of the die should bump the shoulder back (bigger outside part that the lock collar screws onto) is that what your turning? Start with the ram all the way up then turn the die down til it touches (no case in the shell holder) Then turn down in 1/8 increments until you get what you want.

[ctafoya]

I've turned it in 1/2 inch. It won't do chit. I've read a few places that a rcbs full length die will not work for bumping the shoulder back.

[lancetkenyon]

RCBS dies can most definitely bump a shoulder back.

 

All of mine (RCBS and Redding) are set to bump the shoulder back between .0025" to .0010" depending on cartridge.

 

How are you measuring your sized cases? Something like this?

 

http://m.hornady.com/store/Lock-N-Load-Headspace-Kit-With-Body-1-Each/

[C. Cordova]

I've had this happen before. The body of the die screws all the way down and the ram cams over before the shoulder of the case makes contact with the part of the die the bumps the shoulder back. Try the redding competition shell holders. They come in a set of 5 with different thicknesses. The thicker shell holders will allow the case to be elevated more and run the case up into the die further.

[ctafoya]

RCBS dies can most definitely bump a shoulder back.

All of mine (RCBS and Redding) are set to bump the shoulder back between .0025" to .0010" depending on cartridge.

How are you measuring your sized cases? Something like this?

http://m.hornady.com/store/Lock-N-Load-Headspace-Kit-With-Body-1-Each/

That is exactly what I'm using to measure. No matter how far I turn the die in it makes no difference.

[ctafoya]

Can't turn it down much more then this

[C. Cordova]

This is a photo of the redding competition shell holder. One is the thinnest and the other is the thickest. There are three sizes in between that will allow you to choose your desired bump. They are spaced out in .002 increments .

[ctafoya]

Looks like I have some shopping to do. Thanks for all the input.

[WampusCat]

Sounds like a tolerance stacking issue. Your chamber is short enough and your die is just long enough that they can't overlap.

 

If your die and press are camming over without a measurable change in shoulder to base length, you will not gain anything from screwing the die in farther.

 

As mentioned Reddings comp shell holders can help or Redding body only dies will give you unlimited adjustability.

 

Have you measured the shoulder before firing in this chamber and compared it to after firing? Factory rifle?

[L Cazador]

Measure your current shellholder height and then go to Sportsmans and see if they have a competitive brand shellholder that is thinner so you can get the desired bump. If you can't find a thinner shellholder, you may have to make your own, by filing or grinding off a thousands or two at time till you get the desired bump of .001-.002". Measure from the bottom of the shell holder to the top of the shell holder. The top part meets the die and the bottom part meets the ram..

[112coues]

Have you checked your case length?