new project

jbquack1
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new project

Postby jbquack1 » Thu Nov 18, 2010 9:05 am

I have been working on a pistol project and got to the point where i need to cast bullets for the gun.At this point i need the bullets to design my chamber reamer, so I had Dan make 2 molds for me.Both molds are .501 diameter, one being 450 grain and the other is 500 grain.Both have the same nose profile so chambering will be the same.I ran into a snag on the 500 grain bullet, i got greedy with the length inside the case, my case is a 500 s&w cut to 1.4 inches,the bullet ended up too long.Luckily for me, my friend has a smith and wesson x frame gun in the full size chambering(1.625 i think) who wanted that bullet weight/profile combo, so he bought the mold from me.I have been back to the design program and have another design that fits and will be ordering as funds allow, i am getting barrel stock at this point.On a better note, the 450 grain bullet fits, casts and sizes well.Image i have it here next to a .45 colt cartridge with a 330 grain bullet that Dan made the mold for a couple years ago.This is ongoing as time and money allows so more later.Thanks for the great molds Dan.jim

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mtngun
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Re: new project

Postby mtngun » Thu Nov 18, 2010 9:23 am

Sorry the longer bullet didn't work out for your project, but thanks for reminding us that it can be a factor in straight wall cartridges.

jbquack1
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Joined: Sun Nov 09, 2008 8:25 pm
Location: Reno, nevada

Re: new project

Postby jbquack1 » Thu Nov 18, 2010 10:19 am

I think i got too far into the bullet design and quit thinking about the cartridge/intentions.Like i said i sold it for what i had in it :D , and have already played with another design which i will be ordering.Both molds cast great bullets by the way.Casting these big lugs makes me want a 40 pound pot.

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mtngun
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Re: new project

Postby mtngun » Thu Nov 18, 2010 7:07 pm

jbquack1 wrote:Casting these big lugs makes me want a 40 pound pot.
Yep, when you get into the heavier bullets, casting is a whole new ball game in some ways. Most of the casting equipment on the market was designed many decades ago when the most popular molds were 160 gr. 38 specials, 230 gr. 45acp, and 180 gr. 30 cal.

jbquack1
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Location: Reno, nevada

Re: new project

Postby jbquack1 » Fri Nov 19, 2010 10:37 am

Definitely a new ballgame!There are several variables that you talk about here that didn't become critical till i cast 500 grain slugs, I did learn that cooling the sprue plate by wiping the underside of it on a damp rag is more effective at reducing temperature(keeps the sprue from tearing)than just wiping the mold across the rag.At high temps the steel holding in the heat keeps the mold hot.Hope this makes sense.I also found that i should have went about .001 thou larger on as cast diameter and it would have kept my cull rate down, but working with what i had, i added 1/4 pound of 50/50 solder to my 20 pounds of melt and the molds filled out.I spec'd the mold with 2 percent tin, but experimentation has shown me you don't need that much.I also had a slight galling on the top of the mold, i polished out the tool marks and will try it and see if it helps.I never would have thought casting a bullet would require so much thought to get it right.well worth it though.jim

jbquack1
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Joined: Sun Nov 09, 2008 8:25 pm
Location: Reno, nevada

Re: new project

Postby jbquack1 » Mon Feb 07, 2011 9:35 pm

I ordered a reamer for my cylinder Friday.I sent 3 dummy cartridges with the cases made by 3 different manufacturers.I used winchester, Hornady, and Starline.The Hornady and Starline cases loaded and chambered in an X-frame but the Winchester brass needed to be inside reamed before the round would chamber.I measured The case thickness of several of each brand and found the Starline and Hornady to be roughly the same thickness while the Winchester varied 3 to 4 thousandths thicker, when seating my 450 grain cast it bulged the case and would not chamber, it also resized my bottom driving band to .498. A half inch chucking reamer and my mini lathe cleaned the cases up. jim

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mtngun
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Re: new project

Postby mtngun » Tue Feb 08, 2011 8:14 am

Sounds like you are doing a careful job of measuring everything and making sure tolerances are just right. 8-)

jbquack1
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Re: new project

Postby jbquack1 » Tue Feb 08, 2011 8:59 am

Hopefully i can build a "plug and play" pistol, that is set up for cast bullets.I ordered the reamer from PTG, which is right up the road from me in White City Oregon. Good folks to work with as they send you a print for approval , you make any changes you want , they review it to make sure it can be done and then they cut metal. I sent the dummy cartriges as there are wildcats of the same flavor out there, but they typically use off the shelf bullets. My cast have a large front band which is the same on all styles so my bullet position remains constant.I set the throats up so the front band slips in about .080, the throat diameter is .oo1 thousandth over sized bullet diameter, so the fit is good. My next "problem" area is the forcing cone, i am not into formulas, so figuring out what torque to use to counter the rotational force of the bullet without over tightening the shank of the barrel is my challenge. Hopefully i can have this gun test firing by the end of April.jim

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mtngun
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Re: new project

Postby mtngun » Tue Feb 08, 2011 11:52 am

jbquack1 wrote: the throat diameter is .oo1 thousandth over sized bullet diameter, so the fit is good.

Maybe I am interpreting that the wrong way, but normally you want a cast bullet diameter equal to or slightly greater than the throat diameter.

jbquack1
Posts: 42
Joined: Sun Nov 09, 2008 8:25 pm
Location: Reno, nevada

Re: new project

Postby jbquack1 » Wed Feb 09, 2011 8:46 am

Your right, i revised the print to reflect the same diameter as sized. Good catch Dan, i was asleep at the wheel :oops:.Thank you.jim


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