Full bore slug and wad column

[Taylor]

When I first started loading slugs, information seemed to be to use a fiber wad 1 ga smaller than the actual gauge.

For instance: use a 28ga wad in a 20 ga. load. How come we don't use a 20 gauge wad to build the column? I mean...it fits.

[Mr Peabody]

I use smaller when I load in a shot cup. Bore size when I don't use a shot cup. Does that help?

[longbow]

What Mr. Peabody said.

It depends on the slug. If the slug is full bore then you either have to cut petals off a plastic wad or build a wad column... or use something like the BPI flat ended Flex Seal wads https://www.ballisticproducts.com/12ga-Flex-Seal-Wad-250_bag/productinfo/072FS12/.

I started out using the Lyman 12 ga. Foster slug and Lyman recipes which called for cutting petals off regular plastic wads. That didn't work well for the Foster or any subsequent slug loads... for me anyway. The Lyman Foster isn't really a full bore slug as it casts at 0.750". I found that wads were ramming themselves into the hollow cavity.

Some time later I decided to try round balls and got several moulds from 0.662" to 0.735". RB's of 0.662", 0.678" AND 0.690" all fit into plastic shotcups but require a nitro card wad under then to prevent wad distortion and failure. in that case the wads are 15 ga. or 20 ga. to fit inside a 12 ga. shotcup.

Same applies to Lee Drive Key slugs, Lyman Sabot slugs or any other slug or ball that fits into a shotcup. If you need to raise the ball or slug inside the shotcup you use a nitro card wad or two a gauge or two smaller so they fit into the shotcup.

For full bore slugs you use wads that are the correct size for that gauge.

I use a 12 ga. plastic gas seal under a 12 ga. hard card wad column and usually a 12 ga. nitro card wad on top, right under the slug or ball for 12 ga. full bore slugs/balls.

With any hollow base slugs, full bore or wad slugs, the wads tend to push into the hollow cavity unless they are very stiff/hard. With round balls in shoutcup or sitting on top of a cushion leg, the plastic wad tends to wrap around the ball so again a nitro card wad or two solves this. These nitro card wads will be either 16 ga. or 20 ga. for inside 12 ga. plastic wad or 12 ga. (full bore) if sitting on top of a wad column or cushion leg.

Also to note, you mention "fiber" wad. So far I have had best results using hard card wad columns like these https://www.ballisticproducts.com/1_2-Waxed-Hard-Card-wad-200_bag/productinfo/HCW/

What I think of as fiber wads are these https://www.ballisticproducts.com/Fiber-Cushion-Filler-Wad-1_2/productinfo/FC/ which have not worked well for me at all for slug loading.

The short story is:

For full bore slugs use gas seals, card, fiber and nitro card wads that are correct for the bore size: 20 ga. wads for 20 gauge slug/bore.

For wad slugs use a wad that is correct for the bore: 12 ga. wad for 12 ga. bore or 20 ga. wad for 20 ga. bore but use one or two ga. smaller wads inside the shotcup under the slug to raise it up to suit crimp height and/or to keep the wad from pushing into the hollow base.

At 10,000 PSI plastic and card compress and distort and even soft lead slugs will "slug up" to fill the bore if they are undersize and skirts collapse some under the load so a solid wad column is critical to good accuracy.

Make sense?

Longbow

[Taylor]

Thanks guys..somehow I over complicated this --or-- it's an age thing.....pooh.

[W.R.Buchanan]

Kent: Excellent explanation ! That should be a sticky.

Randy