Bullet Diameter after sizing, not matching whats marked on the die. Test.

[243winxb]

Alloy makes a difference-

Tested 4 alloys & 2 size dies. .429" vs .431" The .429" die always produced a .430" finished diameter bullet. When a higher % of pure was added to the mix, the finished diameter got smaller. Less spring back after sizing.

Measure the sized bullet, it may not be the diameter on the H&I die. Different alloys spring back, after sizing, at different rates. I knew this, but got lazy and didn't check finished diameter.

The lighter weights of the bullets is normal, when the % of antimony is higher.

**Alloy composition not known of the pure/scrap/scrap + Linotype metals.**

[DougGuy]

As a footnote, Lee push through sizing dies are made undersized to compensate for springback. If you have a set of pin gages in half thou increments you can gauge the die and see that it won't accept a pin the same size as the die is marked. I suppose other makers do the same but I haven't pinned any besides the Lee dies.

[kevin c]

I know Tom at Accurate requires that the casting alloy be specified since his molds are cut to order and he can alter the diameter bored so that the bullet will drop at the specified diameter with that alloy. Other manufacturers, though, mostly do runs of a specific mold to keep in inventory. Do they have an assumed or default casting alloy to base the bored cavity diameter on? I'd bet that Lyman used #2 alloy, but how about the others?

[Soundguy]

I remember back when if you didn't cast with #2 your bullets didn't drop the grain the mold said..etc.

[45DUDE]

I wish Lee made a .432 flat base 240gr mold with a single lube groove. I bought a new one with all the lube grooves and it drops a .428 which is useless to me. I have a Lyman that drops a .430 but it's a gas check single cavity and takes forever to make boolits.

[fredj338]

Yeah I have taken old bullets & had to resize them.

[fredj338]

I wish Lee made a .432 flat base 240gr mold with a single lube groove. I bought a new one with all the lube grooves and it drops a .428 which is useless to me. I have a Lyman that drops a .430 but it's a gas check single cavity and takes forever to make boolits.

Go to Accurate & get what ever you want.

[ABJ]

Question??? does a specific alloy spring back after sizing or is it just the alloy normalizing or age hardening as some call it.
My 2.5 tin and 4 antimony alloy will reach it's largest "as cast" size in 4/6 wks. I haven't noticed that they change after sizing.
But if I size them before the 4/6 wks I have noticed some changes. This thread just got me to wondering.
Tony

[243winxb]

I kept some sized 44 mag bullets around for years as a test. They stayed right on .430" , never changed. Different alloys? No idea?

Bismuth alloys may change diameters. Like cerrosafe chamber casting alloy.

The bullets in my photo list are going to sit a while. Have to keep an eye on them. They were all cast & sized same day.

Lees molds are regulated using 10 lead 1 tin. 10 to 1.

[Walks]

I've found that springback usually occurs within 24hrs.
But since I'm PC'ing or TL'ing everything these days I usually seat a few dummy's and check the chamber fit. If it fits it gets loaded.

[gwpercle]

I wish Lee made a .432 flat base 240gr mold with a single lube groove. I bought a new one with all the lube grooves and it drops a .428 which is useless to me. I have a Lyman that drops a .430 but it's a gas check single cavity and takes forever to make boolits.

Check the offerings at NOE - www.noebulletmoulds.com - take a look at :
432-237-WC-PB
432-240-WFN-PB
432-246-WC-PB
434-234-RF-PB
Maybe one of these or a slightly heavier design would be just the ticket .
Gary

[Wilderness]

243.... Thanks for the documentation of your investigation re effect of alloy on bullet sizing outcomes. I had certainly wondered at what I had been experiencing. Nice to know I am not alone.

I use #U321297HP cast bullets in .30-30. I discovered, almost by accident, that sizing them down in two stages in Lee dies (nominally .314 and .311) produced my most accurate .30-30 cast bullet.

Alloy is about 10% non-lead, achieved as three parts hardball scrap to one of lino, then fine tuned to a weight as close as possible to 170.0 gns.

My sizing process is to gas check and lube in .323" Lyman #450. Bullet actually casts at .322". Then in one session I size the lubed bullets through both the .314" and .311" Lee dies. They come out of both about .0015" over nominal size, which is to say .3155" and .3125". I put this oversize down to spring back.

Other bullets of softer alloy (5% non-lead) come out of the .311 die at about .3115".

I discovered that the hard bullets if sized again weeks/months later in the .311 die will lose another .0005" to .001".

I am quoting alloys as "% non-lead" because I can estimate this, comparatively at least, by bullet weight.

[243winxb]

Wilderness, sizing down in 2 steps should help accuracy? My mold drops bullets larger then i like or need. But i doubt i could tell the difference, on target, shooting a revolver, these days.

[Martin Luber]

Sounds like the sizer die is more critical than the mould as cast diameter...

I used to be concerned that Lyman moulds cast a few thou over target diameter.

Now I only worry when they're under size, like with pure lead.

[Wilderness]

243 .... the truth is, all of this was a case of discovery by accident. The mould dated from my .32 Special days. More recently, I had put together a .32-40 and dusted off the old mould. Results were uninspiring. I had earlier had some success in the .32-40 with #311407 (.314") patched up to .321", so bought the .314 Lee die to size down the .32 Specials for a try at paper patching. That was another flop. So what to do with the sized down bullets? How about .30-30?

I had some nny cases (now PPU) that were chronically thin in the necks, and which took the sized down bullets and chambered without resistance. Load was 28 gns 2208/Varget at 50 meters, and group in my Savage 99 a bit over an inch. Holy Cow, I'm on to something here! I kept loading them and shooting pigs with them, including reaming out some regular brass to accommodate the oversized bullets. Hunting load by then was pushing 2200 fps, but groups of course not quite so good.

Next step was the .311 Lee die. At .3125" the bullets could be loaded in normal cases and cartridges chambered without interference, and they shot a bit better. The two steps were still required to actually get the bullet into the sizer - the .314 die would accept the .323 bullet, but the .311 would not, and in any case the sizing effort would have been extreme. Initially I had an extra step, which was to run the bullets nose first through the Lyman .321" die after the .323" gas checking and lubing. I have now let that go, apparently without loss. Later I tried sizing down further to .310", but gained nothing from it.

My theories are, first that the Lee dies are the secret for sizing down uniformly, and that a close fit of chamber neck, case and bullet is a big plus. The .30-30 has a rather abrupt entry to the rifling which does not suggest good guidance for a cast bullet - hence the thought that minimal neck clearance for bullet guidance might be more important with these old cartridges than with something like a .308 or .30-06.

As for whether mult-step sizing is beneficial we can only assume the answer is yes. The way it has turned out, I don't mind the spring back either.

[megasupermagnum]

Wow, I always figured harder alloy was bigger, but I've never tested it myself. I figured we would be looking more at tenths, but it appears the difference between pure and lino is about .002". It makes me wonder if there may be more to the old "hard cast" stopping leading, but not because it is hard.

[Soundguy]

Sounds like the sizer die is more critical than the mould as cast diameter...

I used to be concerned that Lyman moulds cast a few thou over target diameter.

Now I only worry when they're under size, like with pure lead.

I'd rather drop large and size down.. vs dropping small.

[GregLaROCHE]

I’ve experienced the spring back effect, especially when trying down size a lot at one time. It was evident as soon as the boots came out of the sizer. I ran them through again and they were better. I never thought to check the next day. Maybe they will grow with time, that I can’t say.

[45DUDE]

Go to Accurate & get what ever you want.

My welfare check ain't that big yet. Thanks