Quoted:
The second.  Not that one, though, it's a countersink style one from RCBS that puts a chamfer on the pocket.  Primers were CCI 500's. The diameter of the pocket was a couple thousandths smaller, I didn't measure the depth.  The primers were getting hung up on the way in, they didn't make it to the bottom of the pocket.

IMHO…..DON'T USE THIS STYLE OF TOOL..........

www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=364181&t=11082005  

Someone once asked: Why Not?

A standard reamer/de-burr tool could be used but, your results will vary greatly.  In my younger days I tried using it but, I encountered problems with getting squared cuts and sometimes over doing it.  YMWV.

Currently, I use these tools......

Large Primer Pocket Size #7777785

www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=682934

Small Primer Pocket Size #7777784

www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=643126

With, the Lyman Hand tool I've eliminated those problems. It has a safe edge on the bottom.....it won't cut the pocket deeper. The cutter will simply spin, via hand power, cutting off the crimp. It'll leave a slight chamfer to the primer pocket opening. It will correct an undersized pocket and an "out of round" condition, but only to the limits of the tool's cutting edge, under hand power. The main pocket diameter won't (under most circumstances) be enlarged excessively, unless you force the tool to the sidewalls. And, the cutting edge can be dulled, IF you wanted to do that. It's a "hand tool" and I wouldn't mount it in a drill........but, that's ME.

BTW, my Speer #10 Re-loading manual has a picture of a pocket knife being used to cut a military crimp out (page 71).

And, for commercial cases, IF needed, the Lyman hand tool will also slightly "chamfer" the primer pocket opening that has that "sharp edge." And, while it's in there.....IF, the primer pocket is too small, it'll do it's magic for that problem, too. Then again, sometimes just changing your brand of primer can work.

Perhaps, using the wrong tool and/or other misusage of a hand de-crimp reamer, may be the reason why, some people are so anti-reamer?

You know the saying about using the right tool for the job?

Well, IMHO......the right tool, is the one specially made for the job of addressing the crimp. In this case, I use a Lyman Hand military de-crimp reamer tool.

Not to mention that, the learning curve is so short. Just insert the tool into the primer pocket, twist, remove the tool and it’s done.  It’s the sort of a mindless operation, that I can do while watching T.V.