Is it mandatory that a cast lead bullet be seated to the top of the lube line.
I am reloading 9mm 122 gr Lead flat points and it seems that if I seat the bullet to the top of the lube line the oal is a lot shorter than the max oal for a 9mm round
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October 14, 2007, 04:00 PM
That's why you start out low and work up your powder charge until you find out what your gun likes. The only important thing about the overall length is that it feed 100% reliably in your gun. Then you figure out what powder charge works best with that length, and keep the length consistant. (maybe that's 2 things...)
October 14, 2007, 04:05 PM
There is no rule that states one must load his ammo to maximum length. However, there is a compromise to be struck between several factors: ammo that is too short may not feed well, seating the bullet too far down in the case may raise pressure in these little cases well above acceptable levels, and finally, ammo loaded too long or short may not crimp or hold the bullet properly. Ammo with too little area bearing on the bullet to grip the bullet may allow the bullet to move into the case as the cartridge goes up the feed ramp and that will raise pressure a lot
Still, this is not all that complicated. Usually the bullet manufacturer will have a suggested seathing depth and sometimes other loading manuals can be read to gain an idea of what will work.
The lube line, or the line at the top of the lube groove, usually is completely covered when one loads ammo. Doing so keeps the lube covered and the dirt out of the stuff.
Many times semi-auto bullets are crimped only to the extent that the crimp barely closes the case mouth around the bullet. When that is so, the only tension holding the bullet is the case itself because there is essentially no crimping hold. Those bullets are also susceptible to being forced into the case as the cartridge goes up the feeding ramp of semi-autos and this phenomenon is obseverved occasionally.
Get in touch with your bullet's mfr., and/or get some good loading manuals that deal with those kinds of bullets.
October 14, 2007, 04:22 PM
Max. OAL for the 9mm is 1.169".
That is to insure they will fit in any brand guns 9mm magazine.
Suggested OAL for the 122 - 124 grain cast Truncated Cone bullet style you are loading is 1.110".
As mentioned, this is to insure proper feeding, and to cover up the grease groove.
Also, if you load this bullet to Max OAL, the straight cylindrical section behind the taper will be so far forward it will jam into the rifling when the round is chambered.
I'd also suggest you pick up a Lyman loading manual if you are going to load cast bullets. It gives you the correct information you need for most cast bullet designs.
Excellent info Bad Flynch. The most important factor you list is dirt and grit accumulating in the bullet lube.
I would only add that the 9mm is taper crimped. I have not seen any of my lead loads set back with even the lightest of crimps. Remember that lead is most often oversized for the bore and the sizing operation will give brass that yields a tight fit with no crimp.
The only other thing would be using a seperate seating and crimping operation, as this will usually give better accuracy.
October 14, 2007, 04:36 PM
The 9mm case also have a very distinct inside taper.
The 124 grain cast bullet will start running into pretty stiff resistance to set-back when the base of the bullet runs into that.