Tuesday, October 16, 2012

Another S&W 78G

A friend made me a good deal (I fixed several of his computers for him as a favor a while back) on a S&W 78G he picked up at a gun show.
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The box.
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Side
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Side
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Side. From the Bangor Punta era.
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All the documentation was there.
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Not the original powerlets, but the original pellets.
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Relatively unoxidized.
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Pellets…
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The pistol has some paint issues on the “slide”.
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The grips also have a white coating.
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Vintage powerlets with the bottle cap.
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Paint problems.
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I used a magnet to remove the power adjuster rod. Unlike the previous one I worked on, the sleeve did not slide out. Darn.
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So I took some stainless steel tubing I had laying around and countersunk one end.
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Fitted a long screw and trimmed the head undersize.
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Added some slots.
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An internal wrench of sorts. I held the tube with pliers and turned the nut to grip.
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Held the end in a vise and gently whacked the slide with a soft face hammer.
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And the tube came out.
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Pile of pistol parts.
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I discovered that the piercing pin was sheared off.
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Only way to grip the pin was in a 5C collet as the large end would have fouled against standard chuck jaws.
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Made it pointier without reducing any of the remaining length.
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And it pierces fine.
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I have one useful tip – holding the trigger down with a zip tie makes reassembly much easier.
I did run into some difficulty though, the pistol had no power. I tried a number of different solutions, lighter valve spring, lubing the hammer, triple checking that the transfer port on the barrel was aligned, replacing all o-rings (I had already replaced the dead original o-rings), etc. Then while reviewing my previous article I realized that I had made the seals from 80 durometer polyurethane rubber instead of the 95 durometer I had used the first time I resealed one…so a new valve seal was made and the pistol functions perfectly. Amazing what a change in hardness makes. I can now disassemble and reassemble this pistol blindfolded.

I’m probably going to clean up the slide and repaint and I’m thinking of making a .20 cal barrel for it as well. Given how long I’ve been taking between posts* we’ll see when that gets done…

*kids & work get in the way these days…

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