If you have been reloading for a long time, you have probably made mistakes. Most of the time those mistakes were not disastrous, but inconvenient. An example would be seating a rifle bullet beyond the specifications on your reloading book. At which case, you would only have to take the bullet out, check your bullet seating die, and seat the bullet to its proper depth.
Reloading as a hobby and as a business deal with potentially sig sauer 10mm dangerous materials. Our cartridges can create very high pressures for being such a small object. Most accidents that occur can be traced back to making mistakes at your reloading bench or at the range.
Over pressured rounds can potentially kill you and at the bare minimum, destroy your firearm. Some signs of over pressure can be bulges in the case or primer separation. Being in a hurry to get to the range and shoot is not an acceptable reason to be careless with your reloading procedures. As simple as switching from slow burning powder to fast burning powder with the same charge can be lethal.
When testing your reloaded ammunition, stopping after the shot seems odd should be a general rule and common sense. Another one that should be is if doesn’t feel right, stop. A good of example of this was a session I had at the range. I had finished reloading 180 grain, lead, round nose, flat point bullets from my 40 S&W. I didn’t realize that one of my reloads was under powdered. When I shot this round, it all seemed “normal.” When the case ejected and the next round was being seated, the slide would not close all the way. The lead bullet had gotten stuck in the chamber and the next round could not seat in properly. Had I forced this round through could have been disastrous to me and my firearm. Luckily, I had stopped to troubleshoot why the round would not chamber and only after disassembling the firearm had I noticed that the barrel had a bullet stuck, or a “squib.” I hammered the bullet out and went home to check my ammunition.
Most mistakes are not made only at the reloading bench, but when testing your reloaded ammunition at the range. Careful scrutiny is needed on what is normal versus what is abnormal. This also includes reading what your cartridge is telling you., such as bulged cases, blown primers, extruded cases when they shouldn’t, etc. Inspecting each case as you shoot each round is safer than not checking them at all. It’s better to err in safety rather than find the consequences due to a lack of attention to detail.