Duane - I sure like the sounds of your 'originals'. They are hunting rifles - 'course my 14 bore shot well enough for target work and was difficult to beat.
Holding the rifle exactly the same each shot is essential for good grouping, especially with heavy kickers. The use of lead sleds and other shooting 'helpers' is very hard on the stock if the shoulder isn't the only thing behind the butt plate. I have some shoulder problem now with torn cartilage, so I use a mangum recoil pad underneath my coat when shooting something that hurts. That takes out all the sting and I'm able to concentrate on sight picture and trigger squeeze.
I thought I needed a slug for a fast second shot, so we (Taylor and I) cut a mould from an old unused one. We used the .6875" drill, ground the tip into a hemisphere and plunge-cut the new cavity. Due to the nominal size of the bullet, I plunger was easy to make - a section of drill. The mould we made turned out a slightly undersized bullet, so I rolled the pure lead slugs on a doubled towel with a very coarse wood rasp. This cuts into then raises the diameter a few thousandths. These bullets then fit with a couple thou interference fit - ie: rifling engraved upon loading. I coated the bullets in 60% beeswax/40% Vaseline lube for perfect performance. Kick - oh you bet it kicked, but out to 60 yards, held the same elevation as round balls. The lightest bullet this mould would cast is about 560gr. - then on up to 1,200gr. Too much of a bad thing.
I then wanted nothing to do with slugs and experimented with paper ctgs. similar to the military ctgs. of the 19th century. I made a tapered plug to roll the printing paper on, making a tapered tube. The reason for the taper is ease of handling and when biting off the small end, little or no power is lost. The small end is then shoved down into the bore. By the time you get the rod out of the pipes, the powder has dribbled down into the breech. The 'snug' fitting ctg. is then rammed down on top of the powder. The paper ctg. wads up beneath the ball and seals the powder gasses behind the ball. I found with the snug paper ctg. that accuracy was identical to cloth patched balls- ie: 1 1/2' at 100 meters off the bags. None of the paper ctg.s caught fire nor smoldered on the ground after being fired. All my paper ctgs. had 165gr. 2F GOEX in them - no fires but excellent accuracy. I used WW alloy balls for the ctgs. In pure lead, the balls for the 14 bore weighed 482gr., while the WW balls weighed 466gr.
Jeff Tanner of the UK makes excellent round ball moulds of any size you want. They fit regular handles & have no sprue cutters. For snipping off the sprues, I use wire strippers, the plyer's type with little holes for different sized wire. They snip off the sprues leaving a tiny tit. This is easily rasped off with one swipe, leaving a ball with no sprue - this is handy for hunting as there is no orientation needed of a normal ball's sprue.
Hope this helps.