Frank Clarke – airgun genius. The conundrum of one of his last inventions.

[pjbingham]

Perhaps to increase life expectancy of the threaded sections. If a pellet is pushed in then the pellet probe is offered up and then without screwing in,the plunger is pushed in pushing the pellet down far enough that as you screw the probe in there is no resistance from the pellet to increase wear in the thread. Over thousands of shots perhaps the inventor feared it would lead to excessive wear. The photo where it’s extended seems to show that the length of the extension is slightly longer than the thread which would make sense. Also the thread appears more tapered on the plunger version with a short collar,perhaps this helped keep the probe straight when loading as described rather than sitting awkwardly on the biting point of a deeper cut thread. Also with the pellet now forward of the transfer port a non returning fixed probe would be sitting in front of the port creating resistance & turbulence in the air flow.
The plunger design sort of reminds me of a spring loaded Stauffer pot to look at.

[ptdunk]

I do like these collectible conundrums....

As said above is it to push the pellet past the transfer port, then retract so as not to interfere with the airflow from the transfer port, as a normal insertor would remain partially covering the transfer port?

Btw thanks for identifying one of these on a Briton I acquired, I had no idea what it was!

Matt.

[DT Fletcher]

The machining, and maybe the materials, look different between the two items. I'd suggest that perhaps these were "after market" accessories, which would explain why they appear to be rare.

[cinedux]

The pellet pusher allows a missile to be stationed muzzleward of the air transfer vent holes and it seals the breech. When the modified version is retracted, compressed air passes through the barrel transfer ports into an empty space previously occupied by the movable pellet pusher. A state of affairs that facilitates,maximum and undisturbed air flow behind a breeched missile.Thus increasing muzzle velocity.

[ccdjg]

Some very interesting and ingenious replies, but no one has hit the nail on the head yet. The function of the retractable pin is much simpler than you might think and is of real everyday practical value. It has been staring peope in the face ever since Quackenbush made the first push barrel pistol in the 1870's, but it took the genius of Frank Clarke 50 years later to see it.

What I don't understand is why the idea was never picked up and used in all the many push-barrel barrels that have been / are being made ever since.

I will leave you guessing a bit longer, as someone may yet have a flash of inspiration.

You will kick yourself when you know the answer.

[ggggr]

John--what is the length of the pin compared to standard--in both positions?

[ccdjg]

John--what is the length of the pin compared to standard--in both positions?

Guy, The picture shows the two types of pin more or less to scale. When the retractable pin is pushed right in it pushes the pellet the same distance into the barrel as the standard pin. I can use both types of pin in my pistol and they give exactly the same performance, provided you remember to push the plunger of the retractable pin in fully and release.

There's a clue in there somewhere.

[pjbingham]

A standard probe would obscure the rear bowled section of the pellet where the concentration of air needs to be,a retractable one leaves that area clear?

[ggggr]

Guy, The picture shows the two types of pin more or less to scale. When the retractable pin is pushed right in it pushes the pellet the same distance into the barrel as the standard pin. I can use both types of pin in my pistol and they give exactly the same performance, provided you remember to push the plunger of the retractable pin in fully and release.

There's a clue in there somewhere.

So John--if you do not push the retractable pin in and try to fire the pistol, will it actually fire a pellet out or does the pellet obscure the transfer port and there is not enought kinetic energy to shift it? Is the engineering good enough so the seals seal and the barrel moves very slowly (A bit like checking the seal of a tap on a tap loader)???

[micky2]

The pellet pusher allows a missile to be stationed muzzleward of the air transfer vent holes and it seals the breech. When the modified version is retracted, compressed air passes through the barrel transfer ports into an empty space previously occupied by the movable pellet pusher. A state of affairs that facilitates,maximum and undisturbed air flow behind a breeched missile.Thus increasing muzzle velocity.

l would have gone along with this one. but it seems like it is not.