Pistol build

Pauly5 wrote: It'll give you time to design it on your head. I really want to make a breech, but am still mulling over how to tackle it. We could combine design. Would that make it a Punga?

It'll give you time to design it on your head.

I really want to make a breech, but am still mulling over how to tackle it. We could combine design. Would that make it a Punga?

Pistol is 450 mm without silencer.

Barrel is 350 mm long.

I made the fill valve to fit an 8 mm fill probe, so it fills exactly like your S510. I have been using a hand pump. Basically 50 strokes from empty and i'm at 1800 psi according to the pump dial.

I have another barrel that I will use to make a shorter pistol with the barrel the same length as the tank.

What a disgusting day outside here in Wgtn. So into the garage I go.

I had a slow leak from the valve, so I have made a new poppet out of a softer material in the hope it will seal easier under pressure. Time will tell, but it is holding so far.

I also made a seat/spacer for the hammer spring and this forms part of the adjuster. Pretty basic, and i'm sure there are better looking ways to do this, but function first right?



You may also notice different grips. I am now using the std Crosman grip frame and some nice grips made by a great craftsman that inspired this build.




So I pumped it up to 1800 psi and the first shot using 18 grn JSB was around 13 fpe, which was a good 3 fpe gain with the spacer. I turned the adjuster a couple of turns and got just over 16 fpe. I'm pretty pleased with that, as it's a good little hunter with that power, without being too loud. The silencer can certainly be made better as it is the one off my 362. The next 6 shots were all in the 16 fpe mark before dropping under.

I also tried a red dot sight I had. I'll see how it feels using it, and it is lighter.

Kruz, I haven't weighed it yet. It's heavier than a 2240, but it's a nice weight. The centre of G is around the front of the trigger.

I will shoot a string later. I am expecting less shots of course, but the numbers will tell. Consistancy is what i'm after

Pauly, what about fitting a reg, like the huma you put in my little Elly?

I plan to get some, but I can also put an adjuster in to create more tension. The more power I get, the less number of useful shots, but it's a case of seeing what happens.

Lots of avenues to develop.

What the numbers show is typical of a non regulated pcp. Also called the power curve. That's what the grapgh shows. A regulated shot string is in theory a flat line until it drops below the reg pressure,

What is happening there is that the tank pressure (1800) is a littler bit stronger than what the current valve/hammer set up can use, so it isn't hitting hard enough to release full energy. Once a few shots are fired and the pressure drops, the hammer can open the valve longer giving a higher pellet speed. So if I filled the tank to say 2500 psi, it would likely have even lower initial speeds.
If I want to utillize higher tank pressure I will need a stronger hammer tension.


This tank is quite small, so I feel that to get 30 + good shots means I have been lucky with this setup.

The variation in the spread between shots can probably be reduced with refining of the firing parts.