After getting through my 9mm fit issues that many here helped with (I'm referring to my thread a couple of weeks ago about getting stuff to fit my PPQ https://www.thehighroad.org/index.php?threads/9mm-case-gauge-pass-plunk-fail.825609/ ) I've made a minor change to my process.
I now drop the just-sized case into the case gauge to ensure it sized correctly. I used to drop finished rounds into the gauge. (I know the gauges don't check COL. I was checking fit in general.) And when I'd do that on finished rounds there were some rounds that officially didn't pass (they stuck out a little) but they'd work/fire anyway. But with this process change I've tightened what I consider "pass".
In the above referenced thread people report that they toss stuff that doesn't pass their case gauge after sizing. A couple of people reported upwards of a 10-15% toss rate from range pickup brass. Since changing my process I'm getting more tossed cases than I thought I would, but probably <5% end up getting the heave-ho.
I have two questions:
1. Why would a case not size correctly? Cheep brass? Old brass? I definitely seem to be finding if I'm tossing a case it's either S&B or Win. Those seem to be the ones with the highest sizing failure rate.
2. I'm intrigued if this issue of cases not sizing "completely" presents itself with folks who use progressive presses. I'm using a RCBS Rockchucker so I'm doing this checking in between manual steps. I get the sense that, once set up, every round that comes out of a L'N'L or a Dillon works just fine. If that's the case, is doing a case gauge check on every case after sizing overkill?
Maybe I've answered my own question in that my rounds worked before I made this change - which would mean manufacturers tend to make their chambers a little "loose" (I'm not commenting on length....but rather diameter) relative to SAAMI.
These things are bugging me and I just want to understand it better.
Thanks.
OR
I now drop the just-sized case into the case gauge to ensure it sized correctly. I used to drop finished rounds into the gauge. (I know the gauges don't check COL. I was checking fit in general.) And when I'd do that on finished rounds there were some rounds that officially didn't pass (they stuck out a little) but they'd work/fire anyway. But with this process change I've tightened what I consider "pass".
In the above referenced thread people report that they toss stuff that doesn't pass their case gauge after sizing. A couple of people reported upwards of a 10-15% toss rate from range pickup brass. Since changing my process I'm getting more tossed cases than I thought I would, but probably <5% end up getting the heave-ho.
I have two questions:
1. Why would a case not size correctly? Cheep brass? Old brass? I definitely seem to be finding if I'm tossing a case it's either S&B or Win. Those seem to be the ones with the highest sizing failure rate.
2. I'm intrigued if this issue of cases not sizing "completely" presents itself with folks who use progressive presses. I'm using a RCBS Rockchucker so I'm doing this checking in between manual steps. I get the sense that, once set up, every round that comes out of a L'N'L or a Dillon works just fine. If that's the case, is doing a case gauge check on every case after sizing overkill?
Maybe I've answered my own question in that my rounds worked before I made this change - which would mean manufacturers tend to make their chambers a little "loose" (I'm not commenting on length....but rather diameter) relative to SAAMI.
These things are bugging me and I just want to understand it better.
Thanks.
OR
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