sizing Lyman 525 beneficial

[wmitty]

Miked some noses and skirts of as cast 525 slugs and noticed the upper diameter was roughly .015" smaller than the skirt diameter. Should the skirt be same diameter as the nose or does it make a difference? I noticed the skirt bulged the Claybusters 12S3 wad slightly when seated and wondered if it should be sized down enough to prevent the bulge. I recently got a Savage 212 and I want to try these in it using HS-6 and the Remington 2 piece (factory buckshot) hulls.

[Mauser48]

I doubt it would help it is just going in a wad and the wad is what deals with all the contact in the bore.

[Mike Robinson]

I cast both the Lyman 525 12 gauge, and 350 20 gauge sabot slugs. My 12 gauge slugs only weight about 506 grains, and the 20 gauge weight about 350 grains. In both cases the "base" diameters are 0.013" smaller than the upper slug diameter. Based upon inspection of some recovered 12 gauge wads (12S4 shotcups) the base of the slug expands so that the rifling is clearly evident on the "base" portion of the shotcup petals, but the upper portion of the slug does not cause the shotcup to engage the rifling, even though it is 0.013" larger in diameter. Part of that is the taper of the shotcup thickness. I get good accuracy with the 12 gauge sabot slug in the 12S4 shotcup (about 1.75" at 50 yards), but generally get slightly better accuracy (about 1.25" to 1.5" at 50 yards)when I put a 1/4" wide (1/16"+ thick) split ring of plastic tubing around the "tapered" portion of the slug within the shotcup. This also extends the rifling marks on the shotcup.

[longbow]

Yes, I just re-read this and realized that you said the nose is smaller then the base. Should be the other way around. Are you getting proper fillout of the mould?

Shotcups have tapered petals so the slug is effectively tapered to suit wad petal taper, as is the Lee Drive Key slug, with the nose being larger diameter than the base.

I'd say you either have a defective mould or you are not getting proper fillout.

Personally I wouldn't worry about bulge unless the loaded round will not chamber easily. If it won't chamber then try a different wad with thinner petals.

Are you using a loading manual recipe and correct components? If so then the hulls shouldn't bulge. Nonetheless, I'd carefully cast some more after pre-heating the mould well then recheck the diameters. If the nose is smaller than the skirt then something is wrong.

Longbow

[r6487]

mine run .680 at the top and .670 at the bottom.

[wmitty]

I made a mistake! I went back and re-measured the diameters and found to my surprise that the skirt is indeed smaller than the top of the "pellet". I came up with .681" - .683" on the top dia. and .667" - .669" on the skirt diameter. Thanks for the explanation for the difference in diameters; i.e., the variation in petal thickness over it's length.