Casting Abnormality

[bullethead]

I cast several hundred .357 bullets (SWC Lyman 150 gr) a month or so ago and ran them thru a Lyman lubri-sizer with a .358" sizer. The alloy is approx Lyman #2. Recently I noticed that the bases of the bullets were flared slightly and measure .362" I have had to run them thru the sizing die again and all is normal. Why did the bases of the bullet expand/flare out? Does the alloy have internal stresses that take awhile to be relieved? Any help/advice.
The die is .358" (Checked with Starrett test equipment) I have had no problems with other bullets except this batch.

[runfiverun]

quite often if you cast then size right afterwards the boolit will gain some size back.
a harder alloy will also springback after going through a sizer.

i have seen lead wire pushed through a size 189 hole come out 191 because of heat and pressure from behind.
so it's not un normal for this to happen, but usually the whole thing springs back the same amount not just one part.

[243winxb]

.004" difference. Not normal, ever IMO. But then i have only been casting for 40+ years. Still learning. :smile: Could it be a Bismuth Based Alloys ???

[MikeS]

I generally lube-size right after casting. My lube is a kind of between a soft one, and a hard one (I just recently found that I can use it without any heat in my Star sizer), and due to the way I store my boolits sometimes the lube comes out of the lube groove, and comes off the boolit, so recently I've started running them back thru the star right before I place them in the case I'm reloading, and have noticed that on some of the older boolits the driving bands get that mirror finish they usually get while actually being sized. I'm not sure if it's because the boolits expanded some in storage, or if it's because some of the boolits were sized in my Lyman 45 (before I had the Star). In either case, I've kind of settled on running the boolits thru the Star a second time at loading time so I know the lube grooves are filled to capacity. I forget where I saw it, but I remember reading that the rifling of the barrel displacing the lube helps pump the lube to where it's needed as the boolit is going down the barrel, and that if the lube groove isn't full that the pumping action might not take place as well. I don't know if there's any truth to this, but I figure the star is about 2' away from the press, and as I sit kind of between them while loading it's a simple matter to put a boolit in the Star's die, pull the handle while the other hand catches the boolit coming out the bottom, and just placing it directly into the mouth of the charged waiting case.

Now that I'm doing this relubing right at loading time, I've considered sizing them using a Lee push thru sizing die right after casting, and storing the boolits without lube on them, and let the final pass thru the star put all the lube on the boolits, rather than just touching up places where the lube came out. Anyone think this might be a better way of doing it? As a side note, when I size in the Star, or the Lee dies the boolits get the same treatment, I tumble lube them in spray on case lube before putting them into the sizer, so really if I use the Lee die, or the Star for the initial sizing operation, I don't see much of a difference.

[runfiverun]

why size them twice?
i just store them as cast then lube them as needed.
you can lube up 4-500 in about an hour then load them right after.

[stubshaft]

I've had slight springback on sized boolits before but never on just one section of it and not to that degree.

[MikeS]

why size them twice?
i just store them as cast then lube them as needed.
you can lube up 4-500 in about an hour then load them right after.

Well, my thought (and I could be wrong) was that by sizing them right after casting, that the boolits are still relatively soft, and so wouldn't require as much effort to size than if I let them sit a month or so before sizing. The second pass thru at loading time is really only to lube them more than to size them. As I said, I used to lube-size right after casting, but have lately been thinking about splitting up the operations, so the stored boolits will be much neater than if they're stored with lube on them which can come off, etc.