gas check mold question

[walker77]

I posted this in the mold section and didnt get any responses. So ill try it here. This is what i posted.

I bought my first gas check mold. And i need to know the basics on this. Like on my other bullets, they need to be a thou or so over slugged size. So do the gas check bullets need to be the same way, or are they more forgiving?

[DIRT Farmer]

Gas checked will be more forgiving in the load devolpment, but still need to match the barrel throat and grove size. I shot .309 in my O3A3 for years. If every thing was perfect it shot well. bought a .312 for a pistol (which matches the throat better on the 03) I found shooting the rifle was a lot more fun . You gotta work with it.

[Bret4207]

Like Farmer said, easier to make work, but they still need to fit. A completely undersized GC is a waste of time and money IMO. It's at least got to ride the lands and preferably bottom out in the groove. The GC SOMETIMES don't need to fill the groove completely like a PB, but they always seem to work better if they do.