45 caliber gas checks

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45 caliber gas checks

Post by mtngun » Sun Feb 10, 2008 6:05 pm

from the old forum:

Dan - I have one of your molds in .462 cast and am looking at buying at least one other set.

Once I got the hang of casting big bullets (430 gr) I am pleased with the casting, but not the gas check.

I have to cull at least an additional 25 to 30% because the gas check doesn't stay on when I remove it from the sizer.

Hornady 45 cal sizing to .460+.

I bought some gas checks from Dry Creek bullets and they stay on, but I have 3000 Hornadys.

I do not have that problem with the 44 molds of yours. I would assume that the hornady's are really made for pistol and bullets of .452-.454.

What can we do with the next set of molds so I don't loose so many with the hornady's?

Or am I just stuck with going to another Gas Check?


Glad you brought that up. We have three issues here.

Yes, the Hornady 45 is a 0.45 pistol check, 0.460" OD, so if you are sizing 0.460" or larger, the sizing die is not going to crimp the Hornady one iota. The Gator 458 rifle check is 0.468" OD, so it gets a good crimp in the die. However, to complicate matters, the Gator seems to want a slightly fatter shank than the Hornady, otherwise the Gator 458 would be a no brainer.

Please note there are two types of Gator 45 checks. The standard Gator 45 is similar to the Hornady. The Gator 458 Rifle check is the one that is unique and appropriate for 45 rifles.

Secondly, check fit is a matter of taste. Personally, I hate to shave lead when I push a gas check on. I hate to get a sore thumb from installing checks. I'd rather they be an easy fit. When I first started making molds, I made them an easy fit, the way I like them. But believe it or not, not everyone is like me. :shock: Some customers like their checks very, very tight.

Third, the dreaded shrunken bullet syndrome really screws up the tolerances on the shank, because that's where all the dross and air accumulate as the mold is filling. The shank may measure 0.425" when I test it, but the customer may only be getting 0.424", or even smaller, due to differences in temperature, alloy, pouring technique, and how he holds his mouth.

After getting a number of complaints about loose checks, I gradually increased the target diameter for some calibers. For example, I used to target 0.424" on 45's, and I usually erred on the small side. Now I target 0.425", and try to err on the large side.

Now you also have the option of a stepped shank. This puts a little ledge even with the crimp on the check, so the check has something to hold on to. It still has tolerances, so it doesn't always work out, but usually the step will make a noticeable difference, holding the check even when the fit is a little loose. I highly recommend it.

I experimented with tapered shanks, similar to Lyman bullets. It sounds like a good idea in theory, but in practice it still is sensitive to diameter tolerances. The diameter is either right or it's not, just like a straight shank. Since the tapered shank is more difficult to lathe bore, and since I could not see a performance improvement, I gave up on the tapers.

If you haven't already, you might try annealling your Hornady checks. It may help.

If you order another 45 rifle mold from me, I highly recommend getting the mold cut for the Gator 458 rifle check, with a stepped shank.

We won't ever ever solve the check fit problem 100%, because there will always be tolerances, and there will always be differences of opinion on how a check should fit. Since increasing the target diameters, I\'ve received a few complaints about sore thumbs and shaved lead. :cry:');