Sigma cast load development.

[ScottJ]

This might belong in reloading and the mods can move if they want but I thought I'd put it here since it's Sigma specific.

Have been working on a cast load using Lee's TL356-124-2R: Lee 2-Cavity Bullet Mold TL356-124-2R 9mm Luger, 38 Super, 380 ACP (356 Diameter) 124 Grain Tumble Lube 2 Ogive Radius - MidwayUSA

I developed one before with RCBS' 115gr conical (they call it round nose but looks like a cone to me): RCBS 2-Cavity Bullet Mold 09-115-RN 9mm (356 Diameter) 115 Grain Round Nose - MidwayUSA It is very accurate and gives no leading but is hard to get to cast well.

In the attached pic the left target shows a magazine full of my first attempt with the Lees over 3.8gr of Bullseye. Not very accurate and more leading than I care for.

On the right is a mag full of the same over 3.9gr of HP38. Got the accuracy back but I still have a small amount of leading. Trying to decide if I can live with it or not. Want to try the RCBS design over the same charge.

The center target is 12 rounds of my 140gr cast SWC out of my 2.5 inch model 66 (double action so I'm kind of proud of it). All groups are from slightly over 7 yards and shot on different days so there is a variance factor of what sort of day I was having each time. All groups show flyers from where I let myself get sloppy.

 

["JJ"]

I know to many reloading ?s will get this moved so I will try to stay on topic.

So when casting bullets for your "SIGMA", do you purchase a lead alloy designed for bullet casting?
I would imagine using misc lead to melt down would lead up the "SIGMA" even worse.

I am just getting into reloading. In fact loaded the first 100 rds last night for my "SIGMA".

We used purchased bullets but were discussing casting.
I would love to pick your brain further, you know to make sure I take care of my "SIGMA"!!

 

[ScottJ]

JJ, I'm using wheel weights with a little solder added to up the tin content.

Pretty standard alloy for cast and I use it for everything from .380 to .44 Mag.

I just got started casting last August but have been a reloader since 1993.

Feel free to PM me questions.

 

[Bill_inBouse]

Scott are you air cooling or water dropping your cast bullets? I also use WW, for my .357 and .45s but water drop both and found the leading problem is just about nonexistent for my target loads.
Still waiting on parts to start casting for the SIGMA 40. Going to use the Lee TL 175 SWC for the first attempt.

Safe shooting.

Bill

 

[ScottJ]

I water drop everything I cast. Makes it easier than have to worry with a pile of hot, still soft boolits air cooling.

My leading is minimal but I think it might be a fitment issue.

 

[.357 mag]

I've tried to reload 9mm for about a year on and off for my Sigma. I'm using .356 lead bullets and I can't get the round to chamber. I have no idea what it is????

 

[mikelain]

I too have been trying to cast bulits with the Lee 124 gr round nose mold as the op has. I am using wheel weights with a little soldier. I queched the bulets in water. I have had leading with anything more than 3.6 gr. of bullseye.
I too tumble lubed with lee liquid alox.

I shot mine in a 6906 not a sigma.

The bullets drop frome the mold at .358 I think this might be my leading problem as the barrel slugs at .355

I have not messed with it in a few weeks I have worn out all my bore brushes.

My same alloy mix works fine with .38 spl all the way to max load with no leading (lead sticking in the barrrel) acuuracy is not great that hot though. 3.6 gr of bullseye with a cast 158 gr swc tumble lubed has worked best in 38 spl.

 

[ScottJ]

The gurus over at the cast boolit forum have suggested I try two coats of Lee's Alox if I insist on using it. Most over there take a dim view of Alox but I've had good success with it.

I didn't get any leading at all with that RCBS mold. It's just a pain to cast. I've loaded a few of those over the HP38 charge to confirm.

I'm wondering if it might not be the base design of the tumble lube boolit. It has a tiny bevel built in while the RCBS design is very square.

 

[Doctruptwn]

I'm using 4.1 gr. of hp-38 with 124 gr missouri bullet small ball. I haven't had any issues with leading at all. The bullet works fine in my Sigma, on the other hand my 1911's hate the bullet profile. My 40 uses a tuncated cone 180 gr bullet from the same co. with 4.9 gr of HP-38 and they work great.

 

[flash60601]

The alloy you use will have a significant bearing on the leading. If you can approach the tried-and-true Lyman #2 alloy mix, you'd probably be better off. "Wheelweights" can be (and often ARE) mixes of virtually unknown trash. If that's all you can find, OK, but generally you need a good slug of pure lead in it if you are starting with mostly WW's.

I get no leading with mine in 9mm, but I size to .356, and I use the old 50/50 Alox/Beeswax in the luber-sizer. My alloy is just a bit more tin than Lyman#2 (90%lead, 5% tin, & 5% antimony, according to supplier, Rotametals. 92-6-2, according to others)

Slug your barrel, and size to the groove diameter, and use an alloy that will obturate correctly for the characteristics of the velocity and barrel (neither too hard nor too soft).

Bullet hardness is not the Holy Grail of cast bullets. BHN of over 15 should be reserved for things other than 9mm.

Flash