After recent discussions with some folks on shotgun slugs and also after reading Cap'n Morgan's post on his Brenneke I decided to revisit a slug design I tried a while ago but with some modification.
Back in 2009 I tried 0.662" round balls drilled for a screw then set them screw up and put a piece of copper tube on top then pumped full of hot melt glue. The came out pretty well and while the wads look bad, the slugs shot pretty well.
The first three photos were posted after shooting in 2009. the next two are the punch/die set and finished bore size slugs.
My reason for trying this was to get nice consistent edges and surfaces which I was not able to get with other forms of Brenneke style slugs. These 0.662" balls and copper tube are a little undersize for standard shotcups so had to be "patched" up to snug slide fit in the barrel.
I tried flaring to bore size using a tube flaring tool but as you might guess, it didn't go too well and I got uneven flares.
In any case, after recent discussions, reading posts and thinking some (always dangerous!) I decided to try making a bore size version again so made up a set of punches to flare and used a short piece of 12 ga. barrel as a female die to limit the flare.
I cut 3/4" lengths of 1/2" copper tube, set onto the short lower punch, slide the barrel section over top, then drop the top punch in and whack a few times with a small sledge. They come out very nicely, quite quickly and they all look the same. They have a nice slide fit to the barrel too.
Then I drilled 0.678" round balls and put short screws in them, set them onto cupped holders with screws up, set a copper skirt on and pump full of hot melt glue.
The resulting assembly weighs 610 grs +/- a bit which is heavier than I would like but a smaller ball would fix that or I can modify a mould I have to make a short Hammerhead like slug that fits into the tube a ways.
The balance point is just ahead of the front copper tube flare so not far behind the center of the ball.
The ball weighs 460 grs. and the tube & glue weigh about 150 grs.
These are intended for smoothbore and I really like the Brenneke and AQ style factory slugs but have been unable to get consistent base wads so far. I have tried jigs and a variety of materials but so far the best for me has been hot melt glue poured into a form set onto the slug. The copper tubing should make for a consistent skirt... I hope anyway!
Another problem I ran into with ribbed Brenneke style slugs was that the ribs collapsed allowing the slugs to tip in the barrel. I tried wider ribs but with limited success. The copper tubing should solve that.
These really aren't a lot of work to make using the punches. It goes pretty quick.
Let's hope they shoot well!
I will post range results when I have them.
Longbow