Hello all. I'm reloading for .45-120 (rechambered Ruger No. 1) using a Lyman #457132 plain-based bullet and have recently gone the route of gas-checking it. I purchased a "Checkmaker" die from Patmarlins to do so, since they make one designed for plain-based bullets. Thought I should give that a try.
Anyone else doing something similar? I'm finding it's working even better than I had hoped for. Very interesting stuff, this making of gas checks. I'm using beer can metal, which appears to be an ideal thickness for this die. If I place the gas checks I make on a bullet sized to .458", the base of the check usually has a wrinkle across its base after sizing. But if I place the check on a bullet sized to .459", no wrinkles and perfectly flat.
Seems to me - when using such a thin metal to make the checks out of - the fit has to be right on the money because it can 'give' under side-ways pressure very easily. But, as it so happens, .459" is what I need anyway, so it's all good.
I wouldn't be surprised if - since they specialize in making such dies - Patmarlins had taken the combination of dimensions into consideration when making them. While waiting for the die to arrive, I asked Pat (of Patmarlins) about the thickness of metal he recommends and he told me that 0.010" (that I was contemplating usign) would be too thick. So I went with beer cans that are 0.0045" and things worked well right from the start.
It makes sense to use thin metal in the case of plain-based bullets anyhow, because you probably don't want to swage too much when putting it through the H&I die.
Anyhow, if someone's interested in how the Patmarlins Checkmaker is used, I recorded a short video, explaining the process - right from starting with an empty beer can - here: