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I just purchased a 2nd Lyman Foster Slug mold, I plan on setting this up and machining it to make a full bore slug.
Question for those who know will .735 diameter be the best overall size, or should I machine this specifically to my barrel? I only plan to increase the diameter on the straight wall, this will allow for a nice ridge for the roll crimp to locate on.
Thoughts ???
Scott
Scott: If you plan to shoot them as cast that might work pretty well. I powder coat all my slugs and that adds one thousands + per side so if I were milling one out I would start a bit smaller. You can always take out more metal. It can't be put back. Gp
I don't know what the "squeeze down" limit is for slugs but I understand that Brenneke makes the Classic to 0.735". It has ribs to crush down but the Lyman Foster is a thin skirted slug with HB pin going past the equator into the nose so I have to think that if cast from soft lead it will squeeze down quite easily... I know they oburate up to bore size and that they will squeeze through a full choke as any Foster is supposed to. On that basis I'd go at least 0.732". It could always be lapped another couple thou, or powder coated or knurled if you wanted larger.
If cast from wheelweights, I'm not sure. I have shot ACWW 0.735" round balls (as cast diameter 0.736") through a rifled gun with 0.727" groove so that's a 0.009" squeeze, though a round ball has little to squeeze at the equator. No pressure signs at all with that round ball over 38 grs. of Blue Dot. Ranch Dog is shooting 0.737" solid slugs through a rifled barrel at 0.731" groove so there's a solid slug being squeezed 0.006". That's quite a bit. I'm thinking 0.003" over bore if smoothbore or groove if rifled should be safe in any gun... especially with HB slug. You will be thickening the skirt a bit but not a lot. If your mould casts like mine the skirt is about 1/16" thick for a 0.705" slug. if you open up the mould to 0.732" you will be adding 0.027" to diameter so about 0.090" skirt. That's not thick.
It would be interesting to get some pressure testing done for same load but different diameter slug from say 0.001" under bore diameter and working up to maybe 0.005" over bore diameter so see what effect the squeeze has on pressure.
gp is right... you can always take more out but you can't put it back!
Longbow
I planned to do the same thing to my Lyman foster mold except I was going to leave an area on the sides untouched thus leaving a lube groove.
Any opinions on if this would be of any advantage?
Check post #10:
http://castboolits.gunloads.com/show...n-foster-slugs
Buckshot did a nice job of that but if I did it I think I'd go with 2 groove or possible 2 bands and one large groove sorta like the old Paradox slugs.
Longbow
i swage mine to.734 and fill the base with beeswax . killed 6 bucks so far
How do you go about swaging them? Do you just squeeze nose to base to make them shorter and fatter or do you swage them into a somewhat different shape?
There was a fellow that posted here a while back that made a knurling system, we'll call it, using a helical gear to swage rifling grooves into the slug which brought it up to bore diameter. He said accuracy was very good with proper fitting slugs. Same idea as you but different route to get larger slugs. I would think simply swaging the slugs larger as you are doing would be quicker and easier.
0.734" sounds like a good number. The slug should fit about any relatively normal bore and squeeze down to suit.
Longbow
exactly, by compressing them in a short section of a cutoff bbl which i honed a few thousands bigger by using a drill ,wooden dowel wrapped with a fine emery cloth, i do this in my press by using different pieces from my 12ga rcbs die set to compress them all to the same dia and height and then when i load them i take the hard card wads and melt bore butter in a pan and soak the wads until they are completely saturated. that way i do not get any leading what-so-ever and accuracy is great.
Rifled gun or smoothbore?
actually, i started out with a smoothbore with same loading and then when i obtained a rifled bbl, i mostly shoot that now. i got good accuracy with both. when i used the smoothbore i made the slugs larger than bore dia and then i used only the bbl as a sizing die by forcing the slug thru the bbl from throat to muzzle. that way they were bore dia all the way thru the bbl and pressure wasn't a worry and accuracy was good. it's nice to share everyones ideas.
You could put a 3/4" ball bearing in the back of the slug and squeeze it in a press or vice to get the base to expand. Then push it thru a section of barrel to resize it.
Simple way to do it.
I like the Helical Gear idea. It sounds like it could be made to work fairly easily.
Randy
Slugger Doug was the helical gear guy. Basically he made a knurler using IIRC two helical gears and a core inside the slug so displaced lead went outward. He had a fairly detailed description posted here and I think on Shotgun World.
I think simply swaging would be easier. Or getting two or three over bore bands machined in the mould.
Longbow