P 68 AT with ASA trouble shooting

[BearGrill]

Hello,
I recently bought a used Sheridan P 68 AT. It came with an ASA that neatly fits HPA tanks. It works, so basic functionality is there. It is a marker made for the German Market, so it came with the F stamp that says the marker won't shoot more than 214 fps.

I have a few problems, after trying it out at the field.

Chronoed it: 100 fps or 160 fps with a random nut that the previous owner put into the hammmer to increase spring pressure.

I ran the marker with a 0.8L 200 bar (3000psi) hpa tank and a reg output of 850 psi.

Looking at the diagrams I found d that the velocity adjustment screw is supposed to be where my ASA is, while the lower tube is a dead end right in front of where I expect the valve. There is no screw to adjust anything.

Is that a normal thing for ASA Sheridans? Is this a German problem? Is CO2 more volatile and results in higher fps? What can I do to increase the muzzle velocity to the allowed maximum of 214 fps (I am NOT asking for help to commit a felony here.)

Random question: I have a Viewloader Triton liying around which seems to share some design similarities (stacked tube, hammer operated) can I use stuff like the valve and springs as replacement parts?

Thank you guys in advance. I tried playing with the pump it was a lot of fun, and id like to keep using that thing. It just needs a little bit more oomph, wedgits and a couple of O rings.

[BrickHaus]

Welcome to the brass bug. Its an addicting habit honestly. These old sheridans are a lot of fun to shoot once you get over their quarks. And the elegance of them is hard to stop loving.

Yous ASA was a common addition to the Pirana Short barrel, Long barrel, and p68 AT pistols. But other stypes of sheridans had different back caps. you can always keep the sheridan hardlines and ASA, but you would need to do 2 things to get the marker working better on HPA valve work, and spring tuning.

One is, do a little valve work to the marker and or drill out the air transfer hole in the body but doing so may require a resolder of any break through. The marker has a small oriface in the valves to be used with the more dense co2 gas of its vintage. You need a valve tool to remove the valve from the body. You can take the valve out, and carefuly open the air passages in that to start and see how it goes.

that with the addition of a better balance of hammer/valve spring combo will getting shooting right as it sits.

You can also buy a sheridan RVA and replace your ASA with the RVA. Palmers pursuit should have RVAs in stock. The killer to this, is your brass body will have 2x unused side holes where the asa mounted. You will also have to remove your hardline, and find a macro or braided hose fitting for the side tapped body. It would ALSO need a way to mount a tank bottomlime as sheridan frames arent built for that. You would end up needing a UMB ( palmers again) to allow bottom line mounting. Of you can make an adapter rail to adapt an autococker frame to it.

Here if a mac 1 annialilator I recently acquired here on the forum. I added the cocker frame and I am honestly swoon. I used at a big game yesterday. It may have been the 94* weather making paint shoot well, but this thing shot better than all of my other sheridans I own.

[BearGrill]

Oh wow, thank you for the response. This sounds a bit more complicated than I had hoped for.

I think I'll opt for the first option and see if I can get a little more air into the system. Is there a way to get the valve out without the tool? I looked for one in germany but couldn't find one. And shipping costs from the US alone are terrifying.

[BrickHaus]

And for reference. This mac 1 is was shooting 290 fps at 850psi on HPA yesterday ( pump field limit was 300)

[BrickHaus]

You will need a valve tool there is a thread cert soldered into the lower tube currently capturing the valve body.

Here is a picture of an early sheridan valve laid out. The far left nut is what is holding it in there. A valve tool has a squareish tip that is also hollow so if can drop around the valve and catch the edges of that nut.


The next brass bit to the right is the part youd want to open up.


Also IF you see a pierce pin (you may have a CA valve already) you can take the pin off to add to volume and flow. But if you do this you are a constant air only pistol, but it seems lile your end goal. On the other hand you can leave the pierce pin and should be able to make it work with the other valve work.

Id offer my valve tool up, but I need it. But we have a pretty cool grpup here. Someone may have a way to ship one your way cheap.

[BrickHaus]

You may have better luck mqking one yourself.

[XEMON]

BearGrill
Where are you located in Europe?
I'll be visiting family in a few weeks and could bring a set of spring to you (ship from the Eu will be much cheaper than from the US).
The springs I have sourced are new. You can always shorten them if it shoot a bit high.

[XEMON]

Spend a lot of times sourcing potential candidates, buying a bunch of springs and testing them to see which ones works ...
This is just a few crazy people who want to put those old relics back on the field 😅

[BearGrill]

I realized something today, which makes me wonder if I am a bit stupid.

I took the beast apart again, this time looking specifically at the air flow paths, wondering if it needs a thorough cleaning.

The bolt has a hole on the bottom between two O rings (one of them is scratched, but I'll replace it soon). The hole is partially obstructed by some kind of screw like thing. The 'screw' is threaded into the inside of the bolt and sticks out into the gas port.

Should there be a screw in there? Should it block the gas port? (Is this the german counter measure against high fps?) Can I take it out or ahead rotate it 90° so it won't be in the way anymore?

[XEMON]

That screw is a "velocity adjustment" ... Think of it as a choke ...
Can you screw it in?
All of mine have the screw short enough to screw in all the way, you may need to source a shorter screw if it is bottom out.