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Case Sizing Inconsistency On RL550B


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I get a variation of up to .005" in my 30-06 cases as measured in a Hornady LnL comparator. Talked to Dillon on the phone today and the tech said this was normal. I realize brass can spring but this is more than I've seen in a single stage.

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  • 3 weeks later...

there is an awesome article out there about the science behind annealing brass. unfortunately i am too new to post the link to the web site here.. so: bisonballistics.com/articles/the-science-of-cartridge-brass-annealing is the url.

many youtube videos out there as well, both diy and buy my machine now. most are good ideas and pretty easy to fabricate. The one I liked best was annealeez.

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I get a variation of up to .005" in my 30-06 cases as measured in a Hornady LnL comparator. Talked to Dillon on the phone today and the tech said this was normal. I realize brass can spring but this is more than I've seen in a single stage.

Where does the .005" variation occur?

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  • 2 weeks later...

jeffabuck, that was a good article on cartridge case annealing. Thanks.

bote, I struggled with (shoulder datum to case head dimension) variations just trying to full length size .223 Rem cases using a single stage O-frame press. The idea that I could fully raise the press ram, screw the sizing die until it abutted the shellholder and then unscrew the die a half turn (0.0357") or so. Then size a case, measure it, screw the die in a tiny amount and repeat until I achieved the dimension I was aiming for, didn't work for me.

It wasn't until I read an article published in Precision Shooting Magazine and some postings on the internet that I began to understand what I was up against. Brass hardness (this is where annealing comes into play) and thickness, case lube type and application, press rigidity and operator consistency were among the variables. Based on what I had read, I decided to try a set of Redding's Competition Shellholders. Following Redding's instructions means that the bottom of the die is always abutts the shellholder (in full contact with the shellholder) when the ram is at the top of its stroke. You simply start with the +0.010" shellholder and work your way down in 0.002" increments until you achieve the dimension you're aiming for. This solved my problem. Based on my experience and IMHO, I would not expect to be able limit sizing variations to an acceptable degree (to me) on my 550.

Edited by 808win
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