Gas Check Fit

Last night I was fighting with the gas checks fitting on the bullets. I found a fix that may have been found before but is new to me. I put my collet bullet puller in my powder measure stand from the bottom upside down adjusted and crimped the gas check stem to allow an easy and non frustrating gas check install before sizing. My fingers enjoyed it the most. So then I played with Plain base bullets and was able to make them accept a check. I used a piece of plastic round rod to set depth. Maybe some of you can use this. :bigsmyl2:

Thanks for the idea. Swaging a gas check shank on a plain base bullet, far out!

If you don't mind, what brand bullet puller? I imagine there might be some differences between the manufacturers collet designs is why I'm asking. I'm just getting into gas checks and this sounds like it might save me some grief.

I'd like to know which bullet puller myself. I bet a lee collet die could be made to work also.

Mold makers that have a good product usually get the size right and checks snap on, cheapo molds not so much.

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Originally Posted by MT Chambers

Mold makers that have a good product usually get the size right and checks snap on, cheapo molds not so much.

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The worst mold I have as far as gas check fit is a NOE. I would consider NOE to sell great products. What alloy and what temp you cast at all effects the diameter the bullet casts, and it is near impossible for a manufacturer to plan for everything. All of my Accurate molds fit GC's great, because you select the alloy you are going to use, and Tom cuts accordingly.

This collet idea is genious. I'm going to have to give it a try next time. It looks like a 243 WSSM Lee crimp die should be perfect for 30 caliber shanks. A 243 WSSM neck OD appears to be .287". The GC shank on a 30 caliber bullet should be around .284"-.285".

It's ideas like this that I love this forum.

I ended up buying a 243 WSSM collet crimp die, although it is likely other 6mm calibers will work. My collet measures .292" ID at rest. The only modification I made was to cut off the excess of the die body, on top of the collet, so that placing bullets on top is easier. I used a chop saw. This does not hurt the function as a crimper. This will still crimp cases no problem, or resize 30 caliber gas check shanks as I'll show.

I did not have any bullets sitting around with a big shank, but I did have these. The shank measures a perfect .284".

Attachment 263688

This is such a slick setup. All you do is set the bullet on top, and pull the handle. Turn in to adjust tighter. In this case, I had it crimp to .280"
Attachment 263689

And here is the bullet, with a shank that now measures .280". I can't see any deformation of any kind.

Attachment 263690

I did not see anything until I went all the way down to .275", where some lines appeared from between the collet fingers. Even here, .010" downsized, I don't think this would impede the gas check at all. I took it all the way to .270" just for giggles. I've got a NOE mold that I want to cast with to try this out for real.

The NOE gas check expander doesn't work well. The Lyman gas check seater doesn't work well. Hopefully this is the answer.

I started making my own checks about 8 years ago. With one boolit the shank is a little big. I compensate by using slightly thinner aluminum flashing for that boolit, and have checks made and stored in baggies that lists size.

I was making plain base gas checks from soda can aluminum and they worked great. Then I started powder coating and only use checks on an NOE 309-150 SP and a Lee 358-158 SWCHP that I rarely load as I don't load and shoot 357 M very much. I have shot that boolit PCd without checks at 1200 fps and didn't notice appreciable loss of accuracy. I may actually remove the shank from the 358-158 mold. If I were shooting a load that required a check I could use a plain base check.