Sizing down bullets..problem

[Bird]

I am using RCBS dies.
Bullets are .359'' as cast from wheel weights water dropped. I initially sized a few with .357'' dies, which came out at .3577''. Tried these for fit in firearm, but need them to be .356''. I purchased .356'' dies, but now the bullets are coming out at .3574''.
Next I tried air cooled wheel weights, and using the .356'' dies, bullets are measuring .3569'' diameter.
RCBS spec their molds to use linotype, or maybe that just for rifle bullets, so I think their dies would be spec'd the same, thus producing an even larger diameter bullet after sizing than the alloy I am using.
Something seems way off here. Any ideas?

[Larry Gibson]

What are you measuring them with and is the tool calibrated?

[Bird]

I am using calibrated micrometer.

[fc60]

Greetings,

RCBS Pistol moulds are cut for 10:1 Lead:Tin alloy. Rifle moulds are cut for LinoType.

Seems the harder the bullet the more springback from sizing.

Dig out your Intrimik and measure the greaser dies. They are machined with "tolerance" and you may have one on the high side.

Cheers,

Dave

[Bird]

I just found this on RCBS site,
Pistol, Black Powder Silhouette and C Sharps Arms BulletsAn alloy of one part tin to ten parts lead.

Maybe I need to try this mix and see how these will size?

[Bird]

Greetings,

RCBS Pistol moulds are cut for 10:1 Lead:Tin alloy. Rifle moulds are cut for LinoType.

Seems the harder the bullet the more springback from sizing.

Dig out your Intrimik and measure the greaser dies. They are machined with "tolerance" and you may have one on the high side.

Cheers,

Dave

Yes, I will measure the dies. It seems a bit strange that both the .357'' and 356'' dies are off, but anything is possible.

[243winxb]

Harder alloys do spring back more. The heat treated bullets (Not on paper) did not spring back more then .430" No more then the linotype bullets.

You 356 die would seen to be the problem? https://www.thehighroad.org/index.php?media/weights-diameters-test.4081/full

My Lyman .356" die, sizes at .3562" to .3568" depending on alloys. Air cooled & heat treated for my 9mm.

[Kraschenbirn]

I agree that you're probably getting springback. Had a similar issue using my NOE push-thru set-up. My 'pistol' alloy (a rough equivalent to COWW) dropped .358+ and sized to .3572 (+/-) using a .356 bushing. Ordered a .355 bushing and boolits now consistently measure just a touch over .356. Oh the other hand, boolits cast from 25-1 for my BPCR cartridges measure =/- .0002 from marked bushing size.

Bill

[slughammer]

You can size a few boolits multiple times and get a better idea of your die size. Better yet would be to cast a few pure lead and size those to measure the dies. For small jobs like that I use a few pieces of sheet lead in a ladle and melt with a torch.

Sent from my SM-G781U using Tapatalk

[Bird]

OK, I cleaned out the pot, and filled it with plumbers lead. After running a few through the 356'' sizer, they are coming out at .3563'', which may work size wise, but I am not sure how soft I can go for a 9mm. I usually use straight clip on wheel weights, and so far that has worked in everything I shoot.
I will make up some dummy rounds and see how they chamber. If that does not cut it, I guess I will get a .355'' sizer to complete the set.

[DougGuy]

And what about the throat in the barrel? You have to be getting close to groove diameter going smaller, not usually a good thing for a 9mm, especially with a hard alloy. What gun what model?

[Land Owner]

Casting 9mm boolits. Sized Plumber's Lead is 0.3563".

I am not following this
Tried these [0.3577"] for fit...but need them to be .356''
a.) Which firearm [DougGuy beat me to it]?
b.) What is the slug diameter (ID) of your barrel [DougGuy beat me to it]?
c.) Is it possible that your boolit, when seated, has "bulged" the case mouth?
d.) What is the evidence that suggests a 0.356" diameter boolit is required?


1.) Slug your barrel. Check its diameter. Write that down.
2.) Alloy boolits of 0.001" to 0.002" LARGER than barrel diameter are suggested as a best fit.

Alloy of 49-49-2 percent Pb-WW-Tin is about 12 BHN and works very well in my pair of 380 ACP Walther PPK. Don't know why this alloy would not work well in a 9mm.

[GregLaROCHE]

Unless I missed, it you didn’t say what size your boolits where dropping out of the mold. Casting temperatures can vary boolit diameter somewhat. Maybe you don’t need to size. Otherwise, consider honing the smaller die to the exact size that works for you. Slugging the bore is a good idea, if you haven’t already done so.

[243winxb]

Avoid using any antimony. This will allow for smaller diameters, after sizing. Pure & tin works, but ups the price per bullet.

[44MAG#1]

I size 9MM bullets in a .357 die using bullets that are 15 BHN and haven't had problems.
Do you have problems with a .357" die sizing of the bullets through trying them in actual shooting or are you having problems due to reading you will have problems?
I have a Hellcat and a Glock M48.

[bosterr]

The longer you wait to size you'll get more springback . Try sizing the same day and I'll bet they'll size close to die size.

[Larry Gibson]

How much time between water dropping to sizing?

How much time between air cooling to sizing?

[charlie b]

I size 9MM bullets in a .357 die using bullets that are 15 BHN and haven't had problems.
Do you have problems with a .357" die sizing of the bullets through trying them in actual shooting or are you having problems due to reading you will have problems?
I have a Hellcat and a Glock M48.

I was about to ask same question. The initial post says the .357 bullets don't fit. Why not? Plunk test? No throat? Bore dia on small side? My experience is that a little larger is better than a little smaller and fit the bullet to the groove dia plus a 'little'. My 9mm has no throat and does not get fed cast bullets.

Second, if the sizing die is too big/small then get another one. I have three for my .308 bullets (.308, .309, .310) and may use any one of them depending on the alloy I am using. Using Lyman #2 air cooled they run almost .001" over, eg, .309 die gets me .310 bullets.

[Bird]

DougGuy, I agree, I will have to P.M. you. I don't really like shipping important stuff as it has the habit of getting lost here.

243winxb, I appreciate your replies and info. Leaving out the antimony seems to make a huge difference.

Larry, the wheel weights, water dropped and AC, were sized 10 days after casting.

charlie b, They kinda plunk, but the throat diameter is .356''. I can see it on an inked bullet in a dummy round. I am not touching the lands.

44mag#1, Have not shot it yet, Just trying to get everything to fit so I can work out powder charge before I go to the range.

bosterr, I am sure you are correct, I will try again today and size after casting.

Land Owner, its a cz75 new. I will try the 50/50+2%. The lands are .345'', and the grooves are .355'' slugged.

Guys, I always appreciate the responses and suggestions. Thank you.
I think the plan here is to load up some of the smallest cast diameter loads I can, and get to the range. I will try a box of factory ammo first, just to make sure there are no warranty issues with the firearm, then get the throat sorted out.

[farmbif]

I'm guessing your loading 9mm. have you tried shooting any of these cast bullets yet? you may find them to work without any problems. ive shot lots of cast bullets run through lube sizer without ever measuring them. ive always strived for the largest size lube die that will chamber in gun. you do not want to shoot cast bullets that are too small. use a good quality proven lube.

[44MAG#1]

Shoot the gun with the bullets you have that are sized the way you have them to see if there is a problem. Don't make a problem unless you have one.

[jsizemore]

I'm shooting 50/50 + 1% Sn. I cast at 700°F and air cool. I size within 1-2 hours of casting. Bullets are still plenty soft and size is a couple ten thousandths over sizing die dimension. I size and lube at the same time. After 2 weeks I load them.

Keep your antimony or cut it slightly and size within a couple hours of casting AC bullets. I use a 356 expander in the Dillon and pulled bullets are squeezed down .0002-3 after seating.

[whisler]

CZ75's are notorious for having short throats. Don't ask how I know.