Commercial cast question

Rick

Moderator
Staff member
Continuing this story, Dennis has finally decided on a bullet design and had Tom at Accurate make a 3 cav aluminum mold which he shipped directly to me, got it yesterday. Don't know where how or why this design came about other than he has been asking questions of a lot of people for some time. The only input he took my advice on was to reduce the lube grooves, he had this thing carrying enough lube for 5 bullets. It's marked 36-2260. Bullet is for subsonic 357 mag, approximately 220 gr relying on momentum to take down 200 meter rams with both a Winchester and Marlin model 94. It will have a profound rainbow trajectory, says he understands that but is determined to prove it'll work. I also tried talking him out of the rebated boat tail to no avail, he says it'll aid ballistics. I doubt very much at subsonic at the muzzle, he says maybe some day he may want to try higher velocities. Oh well. I'll cast him up a few hundred in various form, mostly my 12 BHN alloy, some with the 8 BHN alloy. He'll also get them Star sized at .359", maybe a few at .358". He wanted .357" but he ain't getting that from me. I'll also on some of them only fill one lube groove, shooting subsonic this thing still carries a lot of lube. I'll lube most with LBT Blue, some with Speed Green that I made up a few years back. Should be plenty to give him enough testing, he says if they work he's having Tom cut another mold for the Magma casting machine and Penn will cast his bullets. Couldn't talk him into buying a pot and casting his own but I will be out of the casting business.

8619
 

Rick

Moderator
Staff member
I cast 350 bullets, sized all of them at .359", 2% Sb and 2% Sn and in two days they grew from .3588" to .359". Weight as cast without lube runs 228.5 gr. with my alloy (12 BHN). Lubed all of them with LBT Blue and lubed both lube grooves. He did as I suggested and reduced the lube capacity and they are kinda shallow. Lubing was a bit of a bummer, my Star sizing die only has two rows of lube holes and there was no chance of lining up both lube grooves at the same time, had to lube one groove and adjust the punch and run them all through again lubing the second groove. First I've cast with an accurate mold and Tom did a fine job on it. Bullets fell out without any issues. It's a 3 cav aluminum mold and I had a little trouble keeping the mold from getting too hot, reduced the pot temp from my normal 700 degrees to 690-680-675 and still had to slow down the casting pace.

This morning the bullets and mold will get packed in a medium FRB and shipped off to him, should have them by the end of the week. If/when I get a report on how they do I'll post it here. His goal is much like J.D. Jones Whisper line of cartridges, a heavy for caliber bullet subsonic and let momentum do the work. If he has enough sight adjustment and the twist rate will stabilize them it could work like he wants. The shooting will tell the story.
 
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Rick

Moderator
Staff member
Temperature matters . . . .

Yesterday when I finished sizing/lubing these bullets the shop temp was 71 degrees plus the bullets were slightly warmer because of the heater on the lubrisizer, they measured .359". This morning packing them up I measured a few more. . 358.5". Did they shrink over night? Doubtful, the difference is this morning the shop and bullet temp is 51 degrees.
 

Pistolero

Well-Known Member
At work, all our critical measurement work was in a temperature controlled area, and parts had to be in
that area for 24 hours prior to any critical measuring. All our tool making area, where critical cutters were
manufactured for use on the factory floor, were also temperature controlled.

Yes, temperature matters when you are making precise measurements.

Bill