Solved one PROBLEM...created another,,,

[sargeny1]

HI ALL.....Re the weight variance I was experiencing....turns out I may have been running Lyman #2 at toooo hot a temp(750-800deg)....soooo...turned it down to 650-675 deg,,,,
THAT solved the weight variance big time....was using RCBS 250K mold and RCBS 150K molds....the 250's came in at 250 to 251gr and the RCBS 150K came in at 150 to 151gr....ran a whole pot of Lyman #2 and ended up with 200 250K and 250 of the 150K......BUT....the 250K only miked at .429-.4295".....when I cast at 750 to 800deg I get .431" which give one hole accuracy most of the time.....
the 150K miked at .359" which is fine for my 357's.....

Dang it all....am thinking these .429 are gonna lead....BUT..if I push 'em fast enough maybe I can get enough bump to fill the throats and bbl..??????

Pete

[cajun shooter]

If you have perfect targets with the .431 bullets and then shoot the .429 I think two things may happen. Leading is caused by the hot gases going by the bullets in the bore and leaving lead in the bore. That's why people who cast hard bullets have problems. If your alloy is a true #2 that has been tested to show that then they should upset some. Not as much as a WW bullet. I shoot SASS with BHN 10 or 12 bullets and have never had leading. I also cast at 750 all the time. You fail to say how many of the .429's you have. If it is a lot then I would load up 20 or so and fire them. If a small amount then put them in the pot and turn your heat back up a notch. If you have some tin then you could add it as your problem sounds as if it's coming from failure of mold fill out. This will cause you to have a variable weight between bullets.

[sargeny1]

Thanks Cajun....I cast 200 of 'em yesterday....they are absolutely perfect and weigh in at 250 to 251grains...BUT are .429-.4295".....AND am using foundry certified Lyman #2 Alloy.....THIS batch yesterday is THE BEST cast boolits I have ever made so far....and yes have had best results at .431".....am gonna try pushing them at max 44 magnum velocity and see what happens...
Thanks Again..
Pete

[Calamity Jake]

If you want the .431Ø, go back to 750°. Don't worry about the weight variance so much just weigh sort putting the heavies in one pile the light in another.

You shouldn't get much weight variance @ 750° anyway, so you did something different filling the mold at 650° other than the temp change.

[GabbyM]

Can you press one of the .4295" bullets through your cylinder throats? Good chance that's all the larger they are after exiting the cylinder anyway.
Bullets may also grow a few tenths after a week or two.

It sounds like you are running two moulds at the same time. If you place a six inch fan across your bullet drop area and stay with the single 44 mould you can keep it's temp up and you'll get a larger bullet. With a fan you'll have a four to five second cool down pause with open mould in fans air stream. It takes half that time to set down then pick up a mould and that's all work. I realize some guys like all that excitement but I prefer a slower pace.

[RobS]

Bullets may also grow a few tenths after a week or two.

I hope they don't grow a few tenths after a week or two.

tenths, hundredths, thousandths .1, .01, .001

Gabby: I know what your are meaning though. They can enlarge as they age harden in a few weeks and possibly a thousandths (.001).

cajun shooter probably has it ear marked in that when you came down in temp there was not as good of fill out even if it looks like the bullets are fine.

I don't know what your variance was with casting hotter, but a few grains isn't going to make a difference at a typical revolver range IMHO. As you stated already you had one hole groups with the .431 bullets and somewhat variable bullet weights. I don't know what there isn't to like about that kind of accuracy.

[GabbyM]

I hope they don't grow a few tenths after a week or two.

tenths, hundredths, thousandths .1, .01, .001

Gabby: I know what your are meaning though. They can enlarge as they age harden in a few weeks and possibly a thousandths (.001).

When reading a micrometer a tenth is one ten thousandths of an inch. .0001"

[RobS]

Gabby, I see ya........didn't say you were using a micrometer; on the same page though.

[Edubya]

When reading a micrometer a tenth is one ten thousandths of an inch. .0001"

Hey, I learn something everyday on this forum! I've been using a mic since '65 and never knew that one.

EW

[fredj338]

If you want the .431Ø, go back to 750°. Don't worry about the weight variance so much just weigh sort putting the heavies in one pile the light in another.

You shouldn't get much weight variance @ 750° anyway, so you did something different filling the mold at 650° other than the temp change.

I agree. I never get much variation in wt, maybe 2gr up or down w/ a bullet that large. 750deg is pretty much where my pot stays casting WW alloy or 25-1 for LHP.

[mooman76]

Even if you are getting weight variation I would pick that over leading and accuracy won't loose much if any anyway. Like posted though, you must have changed something because you aren't going to get the variation just because of higher temp. Most like you got it while your mould was warming up to max temp you got. You could preheat the mould better and like also stated you bullets should grow a little within a week.

[Echo]

When reading a micrometer a tenth is one ten thousandths of an inch. .0001"

My dad taught me that before I was out of elementary school. I believe all machinists understand that, when one says 'Tenths', he is referring to ten-thousandths.

[sargeny1]

Thanks to all for your help.....this morning I measure them and they are now at
.4300 to .4305. Which is just what I need.... The 357K are at .3590 to .3595....
Also fine.... They did indeed grow fatter over the last two days....

PETE