Cast Boolits - Gas Checks https://castboolits.gunloads.com/ Using, making and troubleshooting the Gas Check. en Sun, 02 Aug 2026 01:28:36 GMT vBulletin 60 https://castboolits.gunloads.com/images/misc/rss.png Cast Boolits - Gas Checks https://castboolits.gunloads.com/ 6mm gas checks smearing https://castboolits.gunloads.com/showthread.php?488720-6mm-gas-checks-smearing&goto=newpost Wed, 08 Jul 2026 23:59:35 GMT Evening guys, I have cast a good number of bullets and gas checked them with no problems using Lee sizers and Gator checks. I got an RCBS 6mm mold for my sons 243 recently that takes a gas check, and bought a Lee 243 sizer from a member here. I cast up some bullets, powder coated them, and... Evening guys,
I have cast a good number of bullets and gas checked them with no problems using Lee sizers and Gator checks.

I got an RCBS 6mm mold for my sons 243 recently that takes a gas check, and bought a Lee 243 sizer from a member here. I cast up some bullets, powder coated them, and started seating gas checks as I always do. Pointy end of the bullet up towards the sizer, sizing and gas checking in one step. I must have done 50 before I looked to see how well the checks were seated....this is what I found
IMG_20260708_194454608.jpg

What's going on here? The gas checks snap on nicely, but there is this huge dimple in the bottom with copper flowing around the sides. The Lee sizer stem that pushes bullets up measures at ~.240" diameter, but has a taper at the top.

If I flip the bullets gas check up, I get a little some on the gas check and the bullet nose gets slightly flattened. Is this the only way to go?

Sizing first and then gas checking causes the same issue.

Should I cut down the stem to a completely flat top?
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