Jerry: I have recently changed my 9mm post loading procedure. All loaded cartridges are plunk tested in both a Dillon case gauge and a pistol barrel. The Dillon or Wilson case gauge is required because it tests for any burrs or other problems with the extractor rim, which the barrel chamber test will not. I too have had some rounds pass the case gauge but fail in the barrel chamber. Remember, your case gauge is a 'Pistol Max Gauge', not a 'Pistol Min Gauge' This is my latest theory - Sometimes when placing a bullet to be seated, I haven't been careful enough to get the bullet exactly straight and just let the bullet right itself during the seating process. Examining the brass showed that the bullet slightly bulged the casing on one side as it righted itself.
I have been guilty of that also, but I since I crimp separately with the LFC die, it usually fixes that problem. I can tell when this has happened because I usually get a little sliver of lead or copper that comes out of the LFC die when the rd is lowered.
I did figure out what the problem was. The throat on my G3c is tighter than most. These bullets plunked fine in all my other 9mm, but I had to shorten COAL a little more for these to work in my G3c.
COAL is different for each bullet type for a reason. The 9mm cartridge seats on the case mouth. Did you measure the case length to see if it is out of spec? Did you look at the chamber on the barrel to see if there is a burr or crud on the chamber edge?
I have had some experience in my reloading with similar failures. Have you checked the COL of your barrel with the current projectile? Every projectile has a different ogive that can affect the seating depth. I reload a lot of range brass. Check for the Glock bulge. There are specific dies or roll sizers to deal with the Glock bulge. If these are new bullet types you are loading check ogive to the barrel seat. Last check the case head for extraction marks. A small file at the base may correct the problem. Sometimes the brass just springs back too far and won't hold the resizing properly. in this case, dismantle the cartridge save the projectile & primer and discard the casing. This can happen with any case manufacturer.
Thanks, and yes I think you are right. In addition to my tight chamber, I think springback was an issue. I have a Bulge Buster now and it works great. I just save all the mis fits till I get a few dozen, then I set it up and run them thru it. But the Makarov die did work fine until I got the Bulge Buster🙂
Not sure if this will help as i am fairly new to reloading myself, try using the lee factory crimp die and crimp them down a bit. Saw a youtube video with same problem/solution
