Petrol & Powder
Well-Known Member
I purchased a brass, MP 358-165-RF, 4 cavity HP mold and started casting with it.
The mold comes with a fantastic assortment of Hollow Point Pins, including penta-point, cup point, small cone, large cone, and a flat point plug. It’s a well-made mold and comes with Allen keys for the all the fasteners.
I started casting with the Penta point pins because they looked cool! I was immediately disappointed with the accuracy those bullets provided. Replaced the Penta points with the more traditional round, cone type pins and picked the smaller of the pins to achieve the heavier bullet weight.
This was much better in terms of accuracy, but I was getting a lot of variation in bullet weight. The bullets looked good, but I think there were minor variations in the profiles of the pins that resulted in different final weights between the 4 cavities of the mold. The bullets cast with the small pins in place were running 159 to 162 grains. That’s a lot of spread for a 4-cavity mold. Despite the variance, the accuracy was greatly improved.
I decided to try the pins with the larger cone profile and knew I would lose a little bullet weight. My assumption was correct, and the bullet weight dropped to 156 grains but the consistency between cavities was much better and well within a few tenths of a grain over dozens of bullets. I suspect there is one cavity or one pin (or some combination of both) that is slightly different from the others. The difference is so insignificant that I’m not sure if it would be worth the effort to identify the offending cavity/pin.
I have not had the chance to put the large HP bullets on paper, but they are hitting P.O.A. on steel and I suspect they will be at least the equal to the prior lots cast with the smaller pins.
So, I think I’m finally getting off the struggle bus.
The mold comes with a fantastic assortment of Hollow Point Pins, including penta-point, cup point, small cone, large cone, and a flat point plug. It’s a well-made mold and comes with Allen keys for the all the fasteners.
I started casting with the Penta point pins because they looked cool! I was immediately disappointed with the accuracy those bullets provided. Replaced the Penta points with the more traditional round, cone type pins and picked the smaller of the pins to achieve the heavier bullet weight.
This was much better in terms of accuracy, but I was getting a lot of variation in bullet weight. The bullets looked good, but I think there were minor variations in the profiles of the pins that resulted in different final weights between the 4 cavities of the mold. The bullets cast with the small pins in place were running 159 to 162 grains. That’s a lot of spread for a 4-cavity mold. Despite the variance, the accuracy was greatly improved.
I decided to try the pins with the larger cone profile and knew I would lose a little bullet weight. My assumption was correct, and the bullet weight dropped to 156 grains but the consistency between cavities was much better and well within a few tenths of a grain over dozens of bullets. I suspect there is one cavity or one pin (or some combination of both) that is slightly different from the others. The difference is so insignificant that I’m not sure if it would be worth the effort to identify the offending cavity/pin.
I have not had the chance to put the large HP bullets on paper, but they are hitting P.O.A. on steel and I suspect they will be at least the equal to the prior lots cast with the smaller pins.
So, I think I’m finally getting off the struggle bus.
