"Those who forget the past are condemned to relive it"
I just got painfully reminded of this. You may or may not recall my rant last year about how important it is to check your brass and cull the cases who's heads had grown beyond .5010 as the chamber spec is .5010 and they will resist chambering, possibly getting stuck to where you can't extract them if you force them in. I forgot that and just relived it.
I was preparing my next experiment in the Bartz upper, recreating Texas Sheepdawg's 230 FMJ experiment, other than the steel plate punch. That had already been covered. Not wanting to scar up unscarred brass with stab crimps, I rooted around for some previously stab crimped brass and found a jar of cleaned and processed ones to use. Where I faltered was not paying attention to my own label on the side which read "Resized, CHG (case head growth) 5.010-5.015. I spent the long Minnesota winter going through all my brass and meticulously measuring and binning them by CHG. They sure looked nice from having been resized and cleaned. Before checking your brass for CHG, always resize them first.
Anyway, I made sure all the flash holes were deburred and the primer pockets normalized. I then degreased the first .625 inch depth of the inside of the mouths and the primer pockets as well. Now they were ready for priming. I primed them and sorted them into 5 round ranks by overall case length since one step involved a taper crimp. If you don't grasp why, ask. Anyway, I proceeded to charge the different weights with Lil Gun, then seated the bullets ad finally applied the taper and stab crimps.
Don't they look nice?
As a last test before setting them aside until the next range trip, I decided to "thunk test" some randomly selected rounds. Almost every one made a weak thunk, coming to rest rather quietly. That tripped an alarm and I actually tried chambering them by easing the BCA into battery. No Way Jose. Retracting them was next to impossible as well using the charge handle and took considerable effort. I knew better than to drop the bolt and slam them into the chamber as if I had, I'd still be trying to get them out. Now I get to mount the pulling collet die and pull them all down, to recover the powder. The stab crimp leaves the bullets unusable other than maybe as foulers. 50 bullets, 50 primers and a significant amount of my Sunday all wasted.
What a waste of time and material because I forgot the past. I post this to remind everyone in the hopes that you all avoid making the same mistake. Carefully measure your older brass case heads with an accurate micrometer, not an economy caliper and throw the ones in excess of .5010 into the scrap box, or use them to test stab crimps if you use that method
Hoot
FWIW, most of the cases, which I track how many times they had been reloaded, were in the 4 or 5 reload category. Ones with fewer loads in them, unless you load punishers all the time, usually don't suffer from this as it usually is a cumulative problem.