more on bullets

[Halfcock]

Greetings: I am fairly new to this forum and have found both the information and the people to be of great help.

I have noticed that people will often give the standard deviation of the weights of the bullets they pour. The question I have is, does anyone apply stastical process (quality) control principles to their casting? I have cast bullets for many years; everything from .54 minnies to .45 round balls and .45 bullets without paying much attention to anything other than visual defects. Recently I poured about 55 525 gr bullets and 50 of them were within 1 gr of the 525. When I did the stastical analysis, it showed one major and about 5 different minor processes at work. Besides that, 100% of the group fell within plus or minus one standard deviation which is a long way from normal. During the casting session I maintained my 30:1 alloy within ten degrees of 775F.

This certainly is an interesting process to study and it is a data rich environment.

Paul Miller

[RichBratlee]

Hi Paul, You may want to try and cast 850 degrees or so--once I went up to 850 I started seeing a lot less deviation in weight and surface defects

Rich

[RichBratlee]

Hi Paul, You may want to try and cast 850 degrees or so--once I went up to 850 I started seeing a lot less deviation in weight and surface defects---these big bullets need the extra heat to be able to fill out in the mould properly

Rich

[Omaha Poke]

Hey Rich, you been hanging out with Kelley and his itchy mouse finger? Seriously though, I think you are right about a higher temp being needed to fill out the larger weight moulds. I don't use my thermometer much, I go by how the bullets are dropping out of the mould If I get some wrinkles or voids, usually one of two things are happening, the mould is not hot enough or the lead is not hot enough.

I pour about 10 bullets, dumping each of them on the padded towel until I see no imperfections. If I still see imperfections after the mould is hot, I will increase the heat to the lead slightly. Hope this helps, Randy

[Halfcock]

Sorry, my original post stated that all of my bullet weights fell within +/- one standard deviation. The range of bullet weights was +/- one gr. with a standard deviation of 0.5 gr. so the entire distribution fell within +/- 2 standard deviations.

[Halfcock]

Rich & Omaha: Thanks for the info. I tried an 850 temp and the weight spread came down to about +/- 3/4 gr. then I used some Rapine mould prep and the spread came down to about +/- .5 gr. Somewhere in there, I started using a burner from a turkey fryer. Plenty of heat to melt lead and plenty of room to heat moulds. I have been casting a 525 gr. paper patch bullet with the recess in the base. getting an even flow around the recess was a real problem.

This afternoon, at 25 yards, the Shiloh put 5 of those bullets into a ragged hole which could be covered with a $.50 piece. .45-70, Fed 215 primer, 71 gr Swiss 1 1/2, 3 newspaper sheets, 2 wax paper sheets and a .100" grease cookie. Oh yea, those bullets make a very satisfying clang when they hit the gong at 300 yds.

life is good,

Paul

[powderburner]

halfcock if you have problems getting the bases good and your mould is adjustable I have found that if you put the adjst bolt in the melt and heat it up a bit it helps on the base problem the bolt acts like a radiator and disapates heat

[Halfcock]

Powderburner: Thanks for the post. No, the mould just has a little button that fits in the bottom. Raising the melt temp, having a better place to heat moulds and using the mould prep seems to have made this tolerable. Friends told me that a nose pour mould like this would leave me talking to myself; but do I ever listen?

Paul