Boolit growth after sizing

[Tripplebeards]

I cast it up some Lee 200 grain .358 boolits two years ago and sized in a lee .358 sizer. When I measured my bullets after sizing the same day they did measure .358. Well it’s been two years and I pulled the same boolits out and measured them it seems most are .359” to .3595” and a few are .360 to .361! The alloy is used was 50/50 mix of ACCOWW and pure lead flooring with 2% pewter added. The BH was 10.5. I’m guessing to keep consistency I need to resize all these before loading them up. Any idea why they grew so much and at inconsistent sizes? I thought lead actually shrunk in size after so much time?

[Dusty Bannister]

No, lead does not shrink with age. You are seeing the growth and is more noticeable with harder alloys. And the growth is observed as the bullets age harden and the grain structure develops.
You are seeing a bit less than 1% growth. If your bullets were not all the same size when cast, then perhaps that could explain why they are not all the same diameter two years later. Perhaps there is a weight fluctuation as well. That would have nothing to do with hardness but would suggest other variables are playing with your results.

[Tripplebeards]

They were all ran through the exact same lee .358 sizer at the same time and measured .358” immediately after sizing. They just have grown to larger diameters Inconsistently over the last two years. I will end up running them all through my sizer die again that I have now honed to .3595” so they will be back the same diameter.


To be fair I didn’t measure them all at the time I just measured a selected half a dozen or so that all measured at .358” at the time. It seems like the majority of them are .3595” or larger now.

[DHDeal]

Just be glad you didn't load them and they were for a tight cylinder/throat gun. Though not a big deal, you'll be spending some more time with the bullet sizer won't you.

I've got some loaded up (COWW) that were intended for a FA83 357 Magnum. Won't fit in that revolver anymore.

Jacketed bullets sure are easier, but not as much fun.

[DougGuy]

3B don't break your press arm off trying to resize these! Your measurements are very typical with harder alloy. The longer the boolit profile, the more they grow as well. Same boolit in 45 caliber that is shorter and fatter might only grow .0008" - .001" in two years. 480 Ruger and 500 S&W can grow .0015" easily in 6mo.

Once you resize a couple of them, check to see if they go into your throats from the front of the cylinder. You may need to go all the way to .358" with them, and you will get a little springback too so none of them will be .358" for very long.

[Tripplebeards]

I color-coded with PC in one grain increments. I ran my bag of reds through my lee sizing die I honed to .3595”. They all went through with some resistance but all with very, very little effort. Some just barely grabbed and some with a firmer stroke than others. I even grabbed one and ran it through the Sizer a 2nd time in a row and it felt about the same resistance when I ran it through the first time a few seconds prior so there must be some spring back when sizing cast bullets to begin with. I grabbed about a half a dozen of them and they all measured .3595”. I figured the new size i honed the die too should be a happy medium but I can run in both my 35 Remington‘s with a .357” slugged chamber and my Waylon with a .358” slugged chamber that way I don’t mix up bullets I can use whatever I sized and all three of my 35 cal rifles. I would assume the inconsistency in diameters would open up my groups at 100 yards?

[fredj338]

I always thought they grew as well & some split cases in 357mag ammo I had loaded for years tells me they grow.

[Tripplebeards]

What is the max an alloy I can grow?

[ABJ]

I am surprised they grew that much with that alloy. But on the other hand, how old were they on the first sizing? The reason I ask is, if I size before they are a month old then I get similar results as you. If I wait and size a month after cast then the growth is less on long term storage. My alloy is a good bit harder than yours. I'm running 2 percent plus on tin and about 4 percent on antimony.

Tony

[C.F.Plinker]

I am surprised they grew that much with that alloy. But on the other hand, how old were they on the first sizing? The reason I ask is, if I size before they are a month old then I get similar results as you. If I wait and size a month after cast then the growth is less on long term storage. My alloy is a good bit harder than yours. I'm running 2 percent plus on tin and about 4 percent on antimony.

Tony

I too am interested in this aspect of the growth. I try to keep 1000 -2000 unsized boolits in inventory so that I will have them when I need to load. Then I size them right before loading them. After that it might be six months or more before I shoot them.

[Taterhead]

This thread is interesting to me as I continue to try to make sense of all this alchemy.

I had a very interesting observation. Alloy is 3% Sb 1% Sn.

Process was as follows:

Powder coated bullets and sized shortly after completely cooled. .401" on the nose.

Then back into the oven. 1 hour at 420F then quenched. Diameter after cooled and dry grew more than 1 thousandth.

[Petander]

I have some super hard 50/50 mono/ww .500 bullets that have grown unusable in 10+ years.

If I'm going to use them I'll coat them first to anneal,then size. But all that antimony could be used better.

[marek313]

So all this talk makes me wonder then. Wouldnt make more sense to water quench alloy with lower antimony which should result in harder bullet but grow less in size then air cooled alloy with higher percentage of antimony?

Do I mix it to 16 and air cool or mix it to 11 and quench which should probably give me around 16 in few days anyway? One should grow less then the other because of different antimony amount.

This is why I try not to rush loading fresh bullets and instead let them age little bit before.

Also if I have loaded ammo thats been sitting for a while. I usually chamber few before I plan to shoot them just to make sure they chamber correctly. Nothing worse then banging on your AR stock because another 300 Blackout wont chamber all the way and now you cant get it out.

[popper]

I got NOE sizers to check neck and boolit dia so I don't have to mike them. Yup, will spoil your range trip.

[Tripplebeards]

Well this taught me to resize my old cast boolits I stocked up on 2 years ago right before I go to load them. I was having fun when I first got in the reloading and I casted up a couple hundred pounds plus GC, & PC them. Not that big of an issue because I only load maybe 50 to 100 max at a time on average. I did load up about 150 hunting rounds for my 44 magnum rifle. I guess I’ll have to see if some of them chamber next year... And the year after. They’re pretty soft alloy at 7.5bh. It’s a 16 to 1 mix of pure lead and pewter. I’ll be curious to see if they grow or not. I know I cast them last year and loaded them this summer and they shot great. All mine are PCd so I won’t have to worry about relubing them.

[bmortell]

I have yet to see any grow, my oldest boolits are one year roughly. either heat treated 50-50 or heat treated WW are still the same ten thou I sized them too.

[Tripplebeards]

You know I made another post recently about finding completely round lead PCd rings shaved off inside a few of my spent casings. Maybe this would explain why I would get a random ring in a case as some of my boolits grew larger than others and would get large enough to get shaved shaved when chambering into my action???

[bmortell]

ya I was just typing to you there lol. but that's not the solution atleast for me. I usually cast load and shoot in short time spans and some of my projectiles that do that are older haven't grown at all. so there must be another way

[DHDeal]

Well this taught me to resize my old cast boolits I stocked up on 2 years ago right before I go to load them. I was having fun when I first got in the reloading and I casted up a couple hundred pounds plus GC, & PC them. Not that big of an issue because I only load maybe 50 to 100 max at a time on average. I did load up about 150 hunting rounds for my 44 magnum rifle. I guess I’ll have to see if some of them chamber next year... And the year after. They’re pretty soft alloy at 7.5bh. It’s a 16 to 1 mix of pure lead and pewter. I’ll be curious to see if they grow or not. I know I cast them last year and loaded them this summer and they shot great. All mine are PCd so I won’t have to worry about relubing them.

I think you'll find a binary mix (lead/tin pure) won't grow. I've been casting this mix for years for BPCR and after checking some that are stored in MTM boxes, they haven't grown. It's been years since they were cast. The pewter has other stuff in it, so I'm not sure about what that will do.

Like I mentioned in my earlier post, some 357's I cast a year back grew. They were WW + 2%. My FA83 357 Magnum will not accept a .358" bullet without some serious thumb busting so I size in a slightly opened up .357" Lee die.

[Tripplebeards]

The boolits that I measured here were two years old as earlier stated in my post. I sized them with my lee .358 and the biggest one I measured was probably .360”. Some measured .359 and .3595. When I ran all of these through my lee Sizer die that I honed to .3595” the other day everyone of the boolits went through with very little force but just enough that I could barely feel them get squeezed down again inside the sizer. And as I stated earlier I grabbed one and ran it through a second time and it still felt like it was getting squeezed in so there must be some spring back one sizing cast boolits I would assume? I’m using a cheap harbor freight micrometer so I realize that’s my problem as well so what I think is one size could be jumping to another I don’t trust that $10 thing I need to get a good one. Most casters here seem to run .002 to.003 over slugged bore. My 35 rem bores slug at.357” so in all reality I would assume as long as these chamber they probably will shoot very accurately even if I didn’t catch them...correct? I still plan on re sizing them before I load them up with my honed out die that’s .3595” as stated before to keep Consistency. The only reason I measured these boolits to begin with is because I ran them in at 358 Lee Sizer and my 35 Whelen slugged at .358” and figured I’d check them since I needed a larger diameter boolit. I didn’t want any leading and honed my dye to .3595” before hand thinking this would be a happy medium between my .357” sluged 35 Remington’s in my .358” Whelen.... Needless to say I guess I didn’t have to cast a bunch of these boolits, size them at .358, and let them sit for two years.lol so how large will these things get over long periods of time? More than .002?....004?...larger even? Cast bullets are starting to remind remind me of the Dr. Seuss book with the little boy that kept feeding his goldfish. I mean they have to stop growing after so big I would assume.


I just have a gut feeling my 16 to 1 pure lead and pewter mix isn’t going to grow though.