Filling Base of Lyman Foster / Powder Charge?

[Goose18557]

Been working the Lyman Foster 20ga and have gotten some good results. 2" groups at 100yds no flyers yet. After casting I'm tumble lubing and "hammer-sizing" them in an old cut off piece of 20ga barrel. I made the Nose support and base punch out of a low melt alloy. Not perfect but it works pretty good and only cost me a little bit of sweat.

I thinking about filling the bases(with same lead, 50Pb/50WW) after sizing to increase the weight of the slug. Any thoughts on how this might effect the accuracy I am currently getting.

Also looking for input on changes to the powder charge.

-Ithaca Model 37 Fully Rifled 20ga

Current load recipe: 2.75 cheddite / 31gr longshot / OB20 seal / 1/2" hard card / 350 foster filled with modeling clay / 6pt crimp

[uncle dino]

Goose. Another option would be to make a different base pin for mold. Just make it flat, Cast the base solid. I think if you fill base with lead they will separate after leaving the barrel..maybe work ok. I don't know..D

[Goose18557]

D-you think i could still hammer swage a solid cast? Just have to hit it a little harder i suppose.

[OnHoPr]

Sounds interesting. The different base pin sounds good. I don't think I would make it flat though. I did a quick look at one (the mold) and if you were to fill the void you might have too heavy of a slug. It looks like it has decent length for rifling engagement. That is depending on your yardage of hunt and speed with drop. Get to slow and the 10 mph winds will blow that slug around @ 100 yds. Just for the heck of it take a slug and fill the hollow with lead then weigh it to see how heavy it gets. With most 20 ga 2.75 hulls 1 1/8 oz loads are max or magnum loads, so load development may be a little more crucial if you go heavier. At those speeds with 50/50 or WW you won't have any deformation hitting the sand berm behind the target. That means it shouldn't deform on a 3/4" sapling and get real good penetration on deer from almost any angle. If you configured a taper base pin that would bring you up to the 1 to 1 1/8 oz slug, maybe have a depth adjustment on it, you could still flare it to size and have sturdier side walls. Dang that sounds interesting for a 100 yd gun, it sounds like it should even handle the wind a bit on the 75 yd shots. In calm winds 125 yards should be doable. What is your concern with the heavier slug of just another 1/8 or 1/4 oz? Raking shot penetration or something? The 7/8 oz with its available more speed with the same profile might help buck the wind a couple of inches @ 100 yds. Casting with 50/50 or WW should give you the stoutness necessary for almost any angle shot at those speeds.

[uncle dino]

You can make base pin a little long, then keep shortening it till you get your desired weight. You can make it any shape you want. Dish base, cup base, flat..if it's a little long (wont take much) that would leave a small flange on base.that would make hammer swaging a bit easier..d

[Hogtamer]

Goose, may I respectfully ask, "Have you lost your mind?" 2" groups @ 100 yds, what exactly needs improvement? Of course that never stops the rest of us so you may be right at home! I've been looking for my mind for the last couple of years. PM me if it shows up at your place.

[Goose18557]

HT...i have some concerns with terminal performance at 100 yds...don't have a chrono so i dont know exactly how fast my slugs are going out of the muzzle. I also don't know ballistic coeffecient to calculate down range velocity.

In my mind a heavier solid slug helps alleviate those concerns, even if it is traveling slightly slower once it gets there.

[Goose18557]

I decided to continue this "experiment" red neck style while I try and figure out how to make a new base pin without a lathe. I fired up the pot and filled the hollow bases. As predicted by Dino the "core" was fairly loose and fell out as they cooled. The good news is that when I hammer swaged the slug to barrel diameter everything tightened up pretty good. Not sure whether they will stay together during firing but i'm sure going to find out.



Need to work on the pour consistency for the core. Slugs usually drop 348-350. Got variances from 570-585 once they were swaged together with the cores.

[uncle dino]

Goose what's the diameter of that pin where it goes through mold?

[Goose18557]

.4635 in diameter and .7040 from the bottom of the mold to the base of the slug - as measured by my pair of $20 digital calipers

[uncle dino]

I can spin ya one out quick.. I'll make it a little longer. Then you can grind it back as needed..how wide is clip groove..I don't have a Lyman pin here to measure off of..d

[Goose18557]

Thanks D...much appreciated....PM sent

[Tackleberry41]

Be really nice if that base pin could be adjusted.