Different size checks?

[handirifle]

I used some Hornady GC's for my 45-70 loads, and it seemed like NONE of them fit. Well maybe one out of 15 or so stayed on, but most of them fall off. What am I doing wrong? I use a Lee sizing die for this, and if I remember correctly, nose first, but it's been a while.

[454PB]

What size Lee sizer are you using? What is the alloy used?

Some alloys cast smaller. Pure lead casts smallest, and the higher the antimony content, the larger the as-cast diameter.

If the sizer die is too big, or the as-cast diameter is too small, it won't provide enough grip on the gas check.

[Sonnypie]

You have to measure the bullets check shank, and the gas check.
Since they are commercial checks, I would expect them to be very uniform.
The other variable is what you are trying to put them on. If your alloy is too soft, and the check material (copper) is springing back too much, then they won't stay together.
Lead is a dead soft material. Once squished it doesn't swell back up. Check materials can spring open, and then the check falls off.
Can you measure the shank and the ID of the checks?
The Hornady checks I have used were .017" thick. And they stuck real good on Lyman #2 alloy for me. (Abet: 30 cal)
The checks should stay on by themselves before sizing. Then stick even better when formed in your sizer.

[handirifle]

The makeup of the alloy is unknown, to me any way. I will have to do some measuring and get back to you guys with the correct info. As I mentioned, it's been a while, but I happened to see them the other day and figured I better get this resolved.

So it's
sizer die, size
alloy (wheel weights I believe)
The checks have NEVER stayed on before sizing
I will measure the shank (where the check goes) dia
the thickness of the check

Did I miss anything?

[Sonnypie]

The fact that they have never stayed on is a flag right there. Something is amiss.
Shank size is off, or the batch of gas checks is off.
Both commercial and my shop made have been snap on to drive on seating.

I'm suspecting your mold or alloy is dropping undersized shanks.
If you can, get yourself some known alloy to test your mold with. The one I rely on is Lyman #2. And I get mine from RotoMetals.
You may or may not want to shoot it in your 45-70. But for a chunk of metal to compare to it could be a "Standard" for casting for test purposes.
It has long been the alloy of standard that many cast recipes are built around.

If you would like, you could PM me and I could mail you enough of mine (in bullet shaped ingots) so you could cast it for a test. You melt them down and recast in 45-70. Then see how they measure up, compared to what you are currently casting with an unknown alloy metal?
Just a thought....

[Calamity Jake]

Your mold may be casting a small GC shank with a little lapping you can make it bigger, check the stickys for how to lap a mold, also you can anneal the GCs to reduce springback

If all else failes then a little superglue works wonders.

[MGySgt]

There was a Group Buy a number of years ago - a 350 grain GC RD type that had a small GC shank.

Someone here made a reamer (from a hardened bolt) - we passed that around to fix the molds with.

Worked great. I have another AL mould that I SHOULD have used it on but didn't. Gator Checks work fine on that one.