Will (a) smoking hot pot make my doober small? (22 cal Lyman GCs will not stay on)

[ohland]

Old retrobate was trying to gas check some 225415 boolits I cast yesterday with Lyman (old black n white box) gas checks. They weren't consistently staying on during sizing.

Booolit mic .224 (maybe more), gas check shanks mic .206-.208

These boolits were single cavity, smooth faced blocks, sprue screw split lockwasher ends were sanded smooth. BUT.. temps were probably well into the mid 700s (probably high side...).

Casting hot creates smaller boolits? Would Hornady gas checks stay on?

When things sort themselves out, I want to get a RCBS Pro-Melt to get a better handle on the melt temp...

PS. Was reading a CB thread, OP had problems with his 4-20, called Lee. The activator (?) swings are exasperated by casting in wind, due to the space between the control housing and the pot. Supposedly, Lee recommended using aluminum foil in that space in order to ameliorate the swings. OP said it did help, but not eliminate the issue. From my recent casting experience on Sunday, I would agree that casting in the wind does not help the pot stay stable, temp-wise. YMMV

:popcorn:

http://castboolits.gunloads.com/showthread.php?273806-Lee-4-20-casting-pot-help

"2) If the weather is cool especially, but at all times possibly, Mr. Lee said it will be advantageous to stuff aluminum foil between the pot and the closed case the thermostat is in. It will conduct heat from the pot to the thermostat, as the air gap is too wide. Or, one can close that air gap up by turning the nuts to close it up, but I chose the aluminum foil. I don't completely fill the gap with the foil, I just stuff some in (don't worry about the foil touching the exposed coils, they're not conductive on the outside). All of this per Mr. Lee."

[Yodogsandman]

Your alloy would also make a difference. More antimony=bigger boolits.

Even in arctic conditions, a PID keeps the temperatures of a Lee Pro 4-20 constant. It will correct any variations caused by wind very quickly, too but then, I'm out in the shelter of the barn.

[ohland]

Your alloy would also make a difference. More antimony=bigger boolits.

Ow. Here comes math again, and I am not drinking... Where is the info for figuring change in diameter for addition of antimony? Of course, the antimony will be in an alloy...

[bhn22]

You'll want a little higher temps with such a small bullet in an iron mould. If all else is satisfactory with the bullets as cast sizing, consider lightly honing out the gas check step area in the mould to make the check crimp more securely. Many gas check steps are undersized, in addition to being slightly tapered.

"doober"? And who's Amelia Rate, and why is she casting for you?

Are you sure you haven't started.... Never mind.

[Bent Ramrod]

IIRC, the original Ideal gas checks were designed to come off after the boolit had exited the barrel. Not all of them did, which caused accuracy problems sometimes. Some of them tend to stay in the lubrisizer die when the boolit is removed, especially if the lube is sticky and the gas check shank is a little small. Hornady gas checks crimp on, so they can manage a too small gas check shank. The newer Lyman checks are made on the Hornady patent.

It is possible to selectively lap the gas check shank for a tighter fit, but you have to be careful the grinding compound doesn't spread into the rest of the cavity.

[ohland]

You'll want a little higher temps with such a small bullet in an iron mould.
Many gas check steps are undersized, in addition to being slightly tapered.
"doober"?
Amelia Rate, and why is she casting for you?


For WW lead with a few ounces of tin, what temps are we talking about?
Might be that way, but I have only one mold to measure.
The doober is the little gas check shank, of course. What else could it ever mean?
Amelia Rate is a distant relative to Amelia Erhart. She changed her last name so the paparrazzi stayed away
E R H A R T ----> (R) R A T E, silent "H"

[Geezer in NH]

it will if you stick it in it :kidding: :bigsmyl2::bigsmyl2:

[scottfire1957]

Ameliorate is the opposite of exacerbate. One means "to make better," the other "to make worse." Used both alot when I was a paramedic.

[w30wcf]

Ohland,
The "doober" on my 225415 is .214" diameter. Since your mold's "doober" is undersized, as long as the loose g.c. is retained in the neck, it may work just fine. What I have done on one larger caliber mold I have that has an undersized "doober" is to cut a circular piece of paper about 1/4" diameter larger than the caliber, place it over the g.c. then seat the bullet. Makes for a nice snug fit.

w30wcf

[Mike W1]

Don't cast rifle anymore but maybe this file might be of some value. I had an alloy awhile back that REALLY stuck in one of my moulds and a little change in the composition of it made quite a difference in the bullets releasing. Think maybe what you're looking for is tucked in there.

from NRA Cast Bullet Manual
copyright 1979 p. 87
-=-=-=-=-=-=-=-=-=-=-=-=-=-

SHRINKAGE IN CASTING

Q. It is quite noticeable that different alloys produce bullets of
somewhat different diameters from the same mold. Can you give definite
figures on this? It might be worth an experimental program to
establish the effect.

A. This is already know. The basic information was given in
"Solidification Shrinkage," The American Rifleman, December, 1966,
p. 88. The following summarizes the information and relates it to
bullet diameters as cast.

Last Column of the table herewith gives amount of shrinkage as the
cast item solidifies. There is a further contraction of about 1% in
all these alloys as the solidified item cools to room temperature, but
that need not be considered since we are interested here in only
differences.

This definite information exists for only the standard type metals,
which also are the best bullet alloys. For other alloys it can be
approximated, as to both hardness and shrinkage, by interpolating
according to their composition.

For example, the solidification shrinkage on diameter of a
nominally .357" bullet cast of linotype metal could be expected from
the table to be about .0065 x .357" = .0025"-; and in a soft alloy of
lead and tin, about .01 x .357" = .0035". The .001" difference is in
agreement with observation.

For another example, the composition of Lyman No. 2 bullet metal is
given as 10 parts lead, one part tine, one part antimony, which
approximate 8% tin, 8% antimony, 84% lead. (It is also stated to be 90
parts lead, 5 parts tin, 5 parts antimony.) Its physical properties
thus will lie between those of electrotype and stereotype metals, so
its solidification shrinkage may be expected to be about .75%.

This information indicates the solidification shrinkages to be
expected from general classes of alloys in a range of bullet diameters.
Thus, in .001" on diameters:

BULLET DIAMETER, IN.

ALLOY .308 .357 .452
Linotype .002 .0025 .003
Lyman No. 2 .0025 .0025 .0035
Soft .003 .0035 .0045
Pure Lead .0035 .004 .005

The effect on bullet diameter of changing from one alloy to another
in this table is the difference between their shrinkages. - E.H.H.
__________________________________________________ _____________________

Composition, % Brinell Shrinkage
Type Metal Tin Anti Lead Hardness Linear, %

Electrotype 3 2.5 94.5 12 .87
Stereotype 6 14 80 23 .65
Linotype 4 12 84 22 .65
Monotype 9 19 72 28 .65
Lead - - 100 5 1.13
Tin 100 - - app 7 .90
Antimony - 100 - app 50 .47
__________________________________________________ _____________________


ALLOY TIN ANTI LEAD BHN
Monotype 9 19 72 28
Stereotype 6 14 80 23
Linotype 4 12 84 22
Lyman #2 5 5 90 15
Electrotype 3 2.5 94.5 12
1-10 9 0 91 11.5
1-20 5 0 95 10
1-30 3 0 97 9
1-40 2.5 0 97.5 8.5
Lead 0 0 100 5


METAL MELTING POINT
Lead (Pb) 621 °F
Tin ( Sn) 451 °F
Antimony (Sb) 1167 °F


METAL POURING TEMPERATURE
L-T-A Alloys 620-655 *
Linotype 525-560 **

* Recommended by various authorities
** Recommended by a large manufacturer of type metals


%TIN MELTING TEMPERATURE BRINELL HARDNESS
0 619 4
10 577 10
20 532 12
30 490 15
40 445 16
50 400 15
60 370 15


%ANTIMONY MELTING TEMPERATURE BRINELL HARDNESS

0 619 4
6 572 6
8 554 16
10 518 17
15 482 10


from a letter by Dennis Marshall 4/14/87

"On the matter of age hardening or age softening, your generalization
is true (with some qualification) as it pertains to antimonial lead
alloys. As-cast alloys age harden rapidly at first and then slowly
rise to some peak value after which they begin to decline very slowly.
The time to reach the peak varies with alloy content and other details
which are beyond this discussion. In the case of lower antimony
contents such as wheel weight metal containing about 3% Sb, it may take
several years to reach the peak. Thus, in the practical sense of using
the metal for bullet casting, the alloy is age hardening throughout its
useful life. However, with increased alloy content, peak hardness is
reached within a shorter time. For linotype, the peak occurs within 10
to 40 days at about 24 BHN. It then falls to the range 19-22 BHN over
long times. In contrast, nearly all heat treated alloys peak out
within 1 to 20 days and thereafter decline slowly. See also the Q&A in
the American Rifleman, March, 983, p. 67.

[bhn22]

For WW lead with a few ounces of tin, what temps are we talking about?
Might be that way, but I have only one mold to measure.
The doober is the little gas check shank, of course. What else could it ever mean?
Amelia Rate is a distant relative to Amelia Erhart. She changed her last name so the paparrazzi stayed away
E R H A R T ----> (R) R A T E, silent "H"

I heard she's flighty. Forget women, and look for something to make your situation with the bullets better.

[rush1886]

Probably no help with a bottom pour pot, but if you can figure out a way to do it: I've found, even with slugs up to 7mm and 30 cal, that some of my "doobers" will be undersize unless I "pressure cast". With a dipper, and the mold held sideways, put the dipper spout into contact with the sprue plate, rotate 90`, both hands simultaneous, so the dipper is now on top, hold for a 1-2 count, then carefully rotate the dipper away from the sprue plate, leaving a small puddle in the pour hole. This can and does get messy at times, but is quite effective for small doobers. Not having a bottom pour pot, I won't try to describe any adaptation, but if you can figure it out, it may help. The basic idea is to hold a sufficient quantity of lead in the cavity, under pressure,, read gravity, long enough for the doober to gain that 0.001" extra.
Yes, I do ladle/dipper cast. Never could see any sense to a hole in the bottom of a lead pot. Sooner or later, it's gonna leak.