It seems that more people have more trouble loading the 9mm than any other cartridge. I'm not saying I've mastered it but me and the 9mm have reached kind of a handshaking agreement in two BHPs and two Ruger Blackhawk convertibles. The BHPs are fairly easy as I suspect they have generous chambers. The Blackhawks are really fickle.
Here's what I think is happening and we'll get some discussion going.
I size my 9mm to .357", well .3575" to be exact as I made a custom sizer years ago. This works well accuracy wise in all my guns.
I'm using a Lyman TC sizing die and I suspect many of you are in one brand or another.
The OAL of the loaded round seems to be the biggest problem and me and Wally have been bouncing ideas back and forth all winter as to the fix.
Now this all starts with the sizer and being tungsten carbide, in most dies is a small carbide spacer about 3/16" thick which is cemented/staked into the mouth of the sizing die. I haven't measured one but I have measured several hundred heads and the all fall well below .391" which is the 9mm head dimension.
After loading, I checked several hundred 9mm cases loaded with a .3575" 358480 through my 9mm cylinder and has four which failed to seat easily and during shooting and loading would have tied my cylinder up. Measuring these loaded rounds gave me right at .384" OD at the base of the bullet which is a bit oversized but after another trip through the taper crimp die, they chambered fine. These would have fired in the High Powers.
Now, the case mouth on a loaded 9mm should run .380". Doing a little subtraction here, I'm getting .023" for the difference between the loaded round (.380") and the sized bullet (.357"). Half of this is .0115" and I'm pretty sure 9mm brass don't run that thick.
It looks like to me, we're sizing, expanding, seating a bullet which expands the case and then we come back with a taper crimp die and squeeze the whole mess back down to where it chambers.
Now, this is well and good if it chambers and the accuracy is there.
If this is happening, we're using a bullet with a .357" diameter or .357" driving band diameter at the front end and the rear end is swaged town to .356" or maybe as low as .354". If this is happening, the bump upon firing is expanding the rear to chamber diameter to give good accuracy.
Kinda think this is happening. Discussion?????/beagle