Measuring Shoulder "Bump" with Harrell’s Case Collar
Harrell’s Precision sells “semi-custom” full-length bushing dies for the PPC and 6BR chamberings. While the Harrell brothers do not cut the die to spec, they carry a large selection of dies made with slightly different internal dimensions. When you send in your fired brass, the Harrells choose a die from inventory with just the right amount of sizing (diameter reduction) at the top and bottom of the case. Given the quality, and precise fit, Harrell’s full-length dies are a good value at $70.00 plus shipping.
Bump Measuring Collar
The Harrell brothers provide a nice bonus item with each full-length die — a neat, little shoulder bump measuring device as shown in the photo at right. Hornady/Stoney Point sells a stand-alone tool that does the same job, but the Harrell’s bump collar is simpler and faster. To measure your shoulder bump, simply place the Harrell’s bump collar over the front of your deprimed case (before sizing) and measure the OAL with your calipers. Then size the case in your full-length die, replace the collar and repeat the measurement. You want to set your die so the shoulder moves back about .001″ to .0015″ for most applications. (With semi-auto guns you may want more bump.)
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Tags: Bump, Collar, Full-length Sizing, Harrell's, Reloading
One more tip: Use a punch and base, decapping tool or die to remove the fired primer before taking the initial measurement. When working to thousandths, even a slight crater can throw you off by a significant amount.
This is a great tool.
If I would have known such a tool was
available it would have saved me a lot of
time and money.
I have had a machine shop making them for me
for over 10 years now. I have them for every
calibre I reload.
If you use them with Redding competition
shell holders you cad achieve the right
amount of bump back.
Is the tool that Whidden give you with his dies similar to this?