.308 Sizing coming out .305 ???? Help

[ScottScott]

Why are my cast bullets coming out of the sizing die too small?

They go into the .308 sizer at .311 and don’t come out.308.
They are coming out at .305


Lead: range lead
Cast temp: 650-750
Mold: brass .311
Sizing die: Lee .308

[MUSTANG]

1. Is the die new?
2. The die may be mismarked - I have several Custom Made Lee Dies; one is .305 but it was not marked with diameter on the die.
3. Are you using a lube when resizing the bullets?
4. If the dies been used in the past with unlubed bullets there could be a build up of building metal or lead if not Lube was used.


Just thoughts.

[Thumbcocker]

Shoot them .311.

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[Soundguy]

First though is to clean the die.. then push a lubed straight lead ball thru and measure. ( lube the die too )

[toallmy]

That's way off , if it's a new sizing die - unless it's for paper patching .
You may need to open up the die with a split stick & fine sand paper .

[MUSTANG]

That's way off , if it's a new sizing die - unless it's for paper patching .
You may need to open up the die with a split stick & fine sand paper .

Or list it for sale and buy another in .308.

[Dusty Bannister]

If the size die is off by that amount, you might not successfully enlarge the die and retain the round shape. If the die is one of the RCBS or Lyman dies, it will also require a new eject pin. Contact the seller for replacement. Is this measured with a micrometer or caliper?

[BK7saum]

How are you measuring them? I am assuming with the same instrument before and after. improper technique and use of cheaper calipers can give erroneous readings.

But sounds like you have a sizer issue.

[high standard 40]

Shoot them .311.

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I can't speak for the OP, but for me nothing larger than .309" will chamber in my rifle.

[gwpercle]

Lee sizer dies are not closely checked for diameter ... they may be smaller or they may be larger ...
It sorta like a box of chocolates ...you don't know what size you gonna get .
Call Lee and tell them your dilemma ... they should send a replacement and hopefully it is correct .
Hang on to the .305" sizer , you just never know when you might need it .

Your life will be easier ...the less sizing down you have to do . If your rifle will shoot .311" - .310" or .309" then the bigger boolit will require less sizing down from .311".
If it must have a .308" or .309 " size ...then I would get a new mould to cast them to .308" or .309"
The less sizing you do the easier the job is going to be .
Gary

[JonB_in_Glencoe]

ScottScott,
welcome to the forum.
I assume you are new to the casting game?
I suspect the problem is your measuring technique.
That much size difference is highly unlikely with new equipment.
Also, it would take a huge amount of force, to size a long 30 cal boolit down .006"

Please give us some more details.

[ScottScott]

Brand new.

[ScottScott]

Yes, die is brand new.

[ScottScott]

I am measuring with calipers. I take measurements both parallel and perpendicular. Both measurements provide the same .311 measurement. After running through a brand new Lee .308 sizing die I take measurements the same way but now I get .305

[ScottScott]

Actually it take very little force to size down from .311 to .305. My lead hardness is somewhere in the middle as I am using range scrap for my melt.

[fastdadio]

Every mold and sizing die I bought from Lee was under sized. I had to hone out everything Lee I had. The molds have been sold off long ago. I still use the sizing dies because after being honed out, they now size to exactly what I want.

[JonB_in_Glencoe]

you should be using a 0-1" micrometer for measuring lead alloy boolits. It has a slip clutch, whereas a caliper does not. The slip clutch offers a repeatable tension when measuring soft items (like Lead alloy), whereas a caliper is dependent on your thumb, which isn't reliably repeatable.

[charlie b]

Probably just a bad die. If you plan on casting a lot then I'd suggest you get the NOE setup. Then you can buy whatever size bushing you need.

https://noebulletmolds.com/site/product-category/sizing-tools/bushing-push-through-size-die/push-through-size-die-body/
https://noebulletmolds.com/site/product-category/sizing-tools/sizing_kits/

You can fix the one you have. Some very fine sandpaper on a dowel followed by some polishing compound. Doesn't take very much.

[Soundguy]

As a side question... Range scrap? Bhn ? What? 9-10?

What rifle / fps are you shooting this in? You may not be able to push very fast / high pressure, with a soft, non gas check projectile, unless you enjoy cleaning lead out of long rifled metal tubes...

[andrew375]

If the die is new do not do anything to it except send it back. Before you do, take a few bullets, sized and unsized, to someone with a micrometer. Not only will you have an accurate measurement but also an independent verification of the problem, if there is one.

[RickinTN]

In this case he is measuring both unsized and sized with the same equipment and technique. So, even if his technique suffers, it is the same for before and after. I suggest he has a new die which does not size to what it says it does. Return it for an exchange.
Rick

[Larry Gibson]

ScottScott

Do you have any .308 Jacketed bullets that measure .308 with your calipers?

If so see if one of those .308 Jacketed bullets will slip through the Lee sizer. If not, the sizer is indeed under size and you can hone it out or return it to Lee.