Shoulder bump

[SSG Graybush]

SSG Graybush mentioned to "NOT" use the "cam over" technique recommendation by RCBS….. I assume this would be the same for other press manufacturers use similar design.

So, my question, if the case was measured after each "cam over" until the desired setback is achieved, and the die is "locked-in"……should it not repeat on all of the following cases?

If it's a very small difference in setback, assuming the case chambers properly…….will that setback difference have any measurable difference to the hunter and his equipment? That hunter that doesn't have multiple thousands of $ invested in his/her equipment?

Will these near immeasurable differences going to matter…….or is he/she putting Formula1 tires on his/her box stock LTI Camaro thinking it will be competitive on the F1 circuit? I think that many other limiting factors will become apparent! memtb

To clarify, rcbs states to run die down till it makes contact with case holder and cams over. but makes no reference to checking the bump. When what really matters is the bump. If it full cams over ok but the headspace is what should determine where the die is set. Is my point.
edit- I used a poor choice of words so I'll clarify again. you want cam over but at 2 thou bump. For consistency you must press every piece the same. And you should be caming over, but not just blindly setting it so the die touches the shell holder with no regard as to the bump.

 

[Thompsonj]

Ordered the hornady headspace comparator. After doing some research, hornady has a gauge listed as E with 300RUM

 

[1mechanic]

To clarify, rcbs states to run die down till it makes contact with case holder and cams over. but makes no reference to checking the bump. When what really matters is the bump. If it full cams over ok but the headspace is what should determine where the die is set. Is my point.

Like to set where it cams over at the 0.002" bump from fully formed case. Helps keep me from going to fast and not holding the case in the die for a few seconds to keep it from springing back.

 

[MagnumManiac]

For consistent sizing, it is actually beneficial to cam over slightly and hover for 5 seconds before retracting the case out of the die.
Brass holds a memory, if you size it the same each time, it actually likes being there.
Necks are no different…
Just to clarify, I shoot one case 3 times with just neck sizing before I measure and bump shoulders, then that is set for the life of that BATCH of brass.

Cheers.