Cast bullet sizing, actual bullet size compared to sizer

[big5ifty]

I sized a batch of powder coated .38 SWC, sizing in a .358 Lee sizer.

The sized bullets measure .356 . I'm confused.

What size are the bullets supposed to come out of a .358 sizer ?

[oafpatroll]

My 356 and 357 and 278 Lees size to nominal dimensions exactly. What do you bullets start at from the mould? Maybe they aren't being sized at all.

[big5ifty]

They drop big, up to .360 .

They are definitely being sized. The sizer is stamped .358 .

Maybe my electronic vernier is out of whack. I have an engineering quality manual one I can check it against.

[Treeman]

I sized a batch of powder coated .38 SWC, sizing in a .358 Lee sizer.

The sized bullets measure .356 . I'm confused.

What size are the bullets supposed to come out of a .358 sizer ?

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This exactly what i found - I did not have a sizer smaller than the mold dropped.

[big5ifty]

What an eye opener.

My Sheffield 1" micrometer shows 0.358.

The cheapo electronic vernier from Builders is lying to me.

[big5ifty]

On a side note, I also have an old manual engineering vernier from Atelier.

When I was using it to verify the size, I noticed if I moved the bullet further from the end of the jaw, the tighter it became. Holding it closed against the light, it shines through a gap in the last centimeter of jaw.

Pity about that, it's an eight inch version.

[Tripodmvr]

A vernier is handy with COL and other measurements that are OK if not precise. With bullet diameter a micrometer is a must.

[big5ifty]

I just went and picked up an old micrometer set, Moore and Wright 2-6". R600.

It comes with calibration lengths.

Toolsave in Alberton. They still have a few 1" micrometers, different makes, all used, in the R400 range.

[223]

What an eye opener.

My Sheffield 1" micrometer shows 0.358.

The cheapo electronic vernier from Builders is lying to me.

That is quite normal.  A vernier can never be accurate to within 2 thou.  That's what micrometers are made for.

Adendorf sell a cheap Chinese micrometer for around R225, and it works surprisingly well.

[Treeman]

My mold drops smaller than sizer bullets ?
Is it my lead, mold ?
I can size bullet down after powder coating.

[big5ifty]

My mold drops smaller than sizer bullets ?
Is it my lead, mold ?
I can size bullet down after powder coating.

What is stamped on the mould, and what is stamped on the sizer.

Are you using a micrometer for measuring ?

[Treeman]

Far from stuff now, but the mold is a 157 gr 357/38 mold  the 3 sizers are the one undersize standard size and one bigger .356 .357 .358 (this frome memory only).

[big5ifty]

It'll be worth double checking the actual stamp on each of the mould and sizers.

I sized a batch of .38 SWC with an unmarked RCBS sizer, which I forgot to change out after sizing for 9mm.

I though the batch was scrap, so I put it aside and put out another powder coated batch for sizing.

That's when I got confusing measurements from my vernier.

Turns out, with a micrometer, that unmarked sizer is actually .357, so my batch of SWC for .38 are not the normal .358 that I size to, but .357, and the 9mm I sized are also .357.

Cast sized .357 is not a train smash for 9mm, I just need to load a few and chamber test them, and should they not fit, I do have a .356 sizer to run them through.

That's the type of confusion that happens when you try work from a memory that was last fresh years ago.

It does happen that a mould will drop undersize, in which case you can apply one layer of aluminium tape to the mould face to make the bullets drop a little bigger. They call this beagling.

Mould beagling.

[oafpatroll]

That's the type of confusion that happens when you try work from a memory that was last fresh years ago.

It does happen that a mould will drop undersize, in which case you can apply one layer of aluminium tape to the mould face to make the bullets drop a little bigger. They call this beagling.

I long ago gave up on my memory and start every loading session, unless it's a continuation of one from the day before, by verifying my load data from records and checking and setting up my equipment. Nearly did my head in chasing 'anomalies' that were caused by mix ups. It's tedious but probably time saving over all and most definitely reduces my blood pressure.

That beagling idea is a cracker. Haven't come across it before and will try it for 38 bullets from a nominal 356 mold. 

[223]

I size my 9mm cast bullets in a Lee .356" sizer.  They are quench hardened and powder coated.  When I measured them, the micrometer says they are .358". 
Not sure whether this is due to "spring back" or maybe a worn-out sizer die.
They shoot just fine, except when loaded into PMP case, they go too tight into the chamber of one of my Glocks.

I need to slug the sizer with a soft lead bullet and see what size that comes out.