This post describes making #1 cluster buckshot. I posted this already to another thread but it got lost somehow, so I'm trying the new topic route.
Gun Parts sells a Lyman .30 cal round ball mold. Imagine 3 of those pellets cupped in your hand. They roll together in a triangular fashion, kissing the adjacent pellet where circumferences touch. I wanted to modify the Lyman mold so it will throw 3 pellets instead of 1, and where the free pellets in your cupped hand would kiss, I wanted those pellets to be joined to the adjacent one. The join should be strong enough to hold the pellets together till they get to the target, but weak enough so the pellets separate on impact or penetration.
I don't have a lathe. I used a drill press, drill press vise, ordinary high speed drill bit. Drill into the .30 cal cavity with a 19/64 high speed drill bit going only deep enough to change the round cavity profile into the drill bit's profile, and do the same for the cavity of the facing mold block.
Now you have to drill two more cavities per mold block, spaced so they form the triangular pattern of the kissing pellets mentioned earlier. To get symmetry about the perpendicular centerlines of the block face, use two identical spacers whose combined width is close to .135 inches. When you drill into the factory cavity, a spacer is on each side of the mold block which is held in the drill press vise. When drilling the new cavities, you have both spacers on one side of the block, so the block is shifted off centerline the same amount for each cavity. The centers of the new cavities need to be about .33 inches below the center of the factory cavity, but you should do your own calculations and measurements.
While the factory cavity is on the perpendicular centerline of the block, the new ones will be to the left and right of the centerline and below the factory cavity so that the three now give an outline like the three kissing pellets mentioned earlier. Ideally the cavities will not touch but be about 1/64 apart, so you can control the size and thus strength of the join, by opening the lower pellet cavities to each other and the top cavity, which also is the only way of getting lead into the lower cavities I used a Dremel tool for this part. One block face has to end up being the mirror image of the other.
The pellets will not be spheres but have the HS bit profile on each end and a bit if a straight wall in the center. After I drilled the cavities I found considerable tool marks in the cavities, such that it was very likely the pellets would stick. I had to use various bits and polishing grits to get the marks out, and this had to be done by hand. Symmety and precision suffered a great deal. The result was 3 cavities close but not exact where pellet A is strongly attached to pellet B which is weakly attached to pellet C. Pellet C is NOT attached to pellet A, and there is a .03 inch gap between A and C, and the unit can be pinched to make them kiss if desired, such as to weaken the B-C link or to use in a hull where the wad hasn't had its petals cut off.
I use these three units/9 pellets (513 grains) to a hull. I moly coated them to avoid barrel scraping, as I use the Active T35 wads with the petals cut off in 2 inch hulls mostly. I'm getting 1120 fps in Federal buckshot hulls with 23 grains of Unique, 920 fps in other Federal hulls where the wad doesn't bottom out on the powder..still under developement. I'm also trying 25 grains SP83 for 980 fps and a lot of unburned powder. It's a basically simple concept, despite how I describe it.
John Stamp
Gun Parts sells a Lyman .30 cal round ball mold. Imagine 3 of those pellets cupped in your hand. They roll together in a triangular fashion, kissing the adjacent pellet where circumferences touch. I wanted to modify the Lyman mold so it will throw 3 pellets instead of 1, and where the free pellets in your cupped hand would kiss, I wanted those pellets to be joined to the adjacent one. The join should be strong enough to hold the pellets together till they get to the target, but weak enough so the pellets separate on impact or penetration.
I don't have a lathe. I used a drill press, drill press vise, ordinary high speed drill bit. Drill into the .30 cal cavity with a 19/64 high speed drill bit going only deep enough to change the round cavity profile into the drill bit's profile, and do the same for the cavity of the facing mold block.
Now you have to drill two more cavities per mold block, spaced so they form the triangular pattern of the kissing pellets mentioned earlier. To get symmetry about the perpendicular centerlines of the block face, use two identical spacers whose combined width is close to .135 inches. When you drill into the factory cavity, a spacer is on each side of the mold block which is held in the drill press vise. When drilling the new cavities, you have both spacers on one side of the block, so the block is shifted off centerline the same amount for each cavity. The centers of the new cavities need to be about .33 inches below the center of the factory cavity, but you should do your own calculations and measurements.
While the factory cavity is on the perpendicular centerline of the block, the new ones will be to the left and right of the centerline and below the factory cavity so that the three now give an outline like the three kissing pellets mentioned earlier. Ideally the cavities will not touch but be about 1/64 apart, so you can control the size and thus strength of the join, by opening the lower pellet cavities to each other and the top cavity, which also is the only way of getting lead into the lower cavities I used a Dremel tool for this part. One block face has to end up being the mirror image of the other.
The pellets will not be spheres but have the HS bit profile on each end and a bit if a straight wall in the center. After I drilled the cavities I found considerable tool marks in the cavities, such that it was very likely the pellets would stick. I had to use various bits and polishing grits to get the marks out, and this had to be done by hand. Symmety and precision suffered a great deal. The result was 3 cavities close but not exact where pellet A is strongly attached to pellet B which is weakly attached to pellet C. Pellet C is NOT attached to pellet A, and there is a .03 inch gap between A and C, and the unit can be pinched to make them kiss if desired, such as to weaken the B-C link or to use in a hull where the wad hasn't had its petals cut off.
I use these three units/9 pellets (513 grains) to a hull. I moly coated them to avoid barrel scraping, as I use the Active T35 wads with the petals cut off in 2 inch hulls mostly. I'm getting 1120 fps in Federal buckshot hulls with 23 grains of Unique, 920 fps in other Federal hulls where the wad doesn't bottom out on the powder..still under developement. I'm also trying 25 grains SP83 for 980 fps and a lot of unburned powder. It's a basically simple concept, despite how I describe it.
John Stamp
