So, I'm working with Tom at Accurate Molds to help me design a mold I can use for 9mm and 357/38. I wanted something in the 125 grain range because load data is ample for both calibers in this weight. I also want to conserve lead for my revolver loads. Those bullets I cast drop at about 160 grains, and that really adds up. The sectional density of the standard 115 grain 9mm bullets is pretty low, and this will improve that. But there are some challenges here.
Obviously the revolver won't care about overall length so long as it chambers, but the 9mm will. The bullet shape of the design I'm proposing to him most closely resembles the truncated cone (TC), and typical load data for this generally specifies a 1.10 OAL. Using a TC bullet on hand that I sized to .3575, I found I was able to seat it out to an OAL of .144 and it still chambered OK, and it fits in the magazine as well. Thus, I figure a similarly shaped bullet, sized to .357 and seated to less than .144, should easily chamber and feed.
My internet 'research', always taken with a grain of salt, indicates chambers on Beretta 92s to be generous, being mass produced and all. I also have found accounts of reloaders using .357 and even .358 cast bullets in the 125 grain weight range. If I find that for some reason, that chambering becomes a problem, I can always size down to .356, but I doubt that will be necessary. I can also seat more deeply and drop the charge a bit.
My plan is for the mold to drop bullets as close to .359 as possible and to lube-size them to .358 for the revolver (or .359 if possible), and to .357 for the 9mm.
This is what I'm starting from. I'm going to eliminate most or all of the step-down, which should not be necessary for a production chamber, in favor of a third driving band. Then, separate that band from the middle band by a narrow, shallow crimp groove in case I want to roll crimp. I also propose that top driving band should be about 3/4 the height of the bottom band. Further, I'm asking that he increase the capacity of the lube groove by making it square, or squarer. I may also ask him to reduce the meplat from .18 to the minimum his tooling permits, which is .14.
I'm quite glad that his tooling does not allow for round nose bullets. I've never liked those because they don't self-align very well during the seating operation. The word that come to mind is 'cattywampus'.
One other thought...this is strictly a range gun, so I have no worries about potential reliability issues.
It's accuracy I'm after. I'm roughly modeling this after a 245 grain 44 bullet that he helped me design. Not bragging here, but that one turned out to be a real long-distance champ.
Any thoughts, comments or smart remarks?
New mold for 9mm and .357
1Hell is where:
The British are the chefs
The Swiss are the lovers
The French are the mechanics
The Italians make everything run on time
And the Germans are the police
The British are the chefs
The Swiss are the lovers
The French are the mechanics
The Italians make everything run on time
And the Germans are the police