Expanding Gas Checks for an Oversized Bullet Shank

Using a LEE Universal Case Flaring tool as a Gas Check Expander


Used my new LEE GC expander today (not by LEE). It only works on 30cal that I know of. I have one mould with a slightly oversize GC shank making it difficult to install checks.

I looked around at all the stuff I have accumulated and came up with the following. I used a LEE universal case flaring die with the large expander on the bottom and small one on top.

I then used the push pin from a LEE 30cal boolit sizer perching a GC on top. Running it up in my press the tapered tip of the large universal expander die expanded the check to a perfect slip on size and not a one stuck on the expander. It didn’t take long at all to expand a hundred checks.

You can also try one of these:

It might help as well and works with all calibers. It puts a little chamfer on the base.…products_id=28

Noe’s Gas Check Seating Dies
Once I got a partial box of Hornady .44 GC for a real good price. Turns out the checks were odd to the point of not working on a GC boolet. One day out in my barn I came on some ball bearings of from 3/8 up to 3/4″. I took some to my loading area and tried placing different sized bearings on the GC then tapping the bearing with a plastic mallet. VIOLA! The checks opened up enough to work on shanked boolets!
You have to be careful forcing GCs on. I was doing that and shaving a little lead off of the shank and jamming it into the small gap between the check and the first driving band. I don’t know if that really caused a problem but I didn’t like it.
After starting a GC I still use the GC seater on my Lyman 450 to make sure the check is seated. Before expanding the check I couldn’t even start the check.