Sheridan "tuning".

[Jordan]

Can 12 gram Sheridans be tweaked like Snipers/Cockers?

My KP gets about 5 good shots from a 12gram, the rest are what I would consider unuseable.

I cut a couple coils to try to reduce the two initial hot shots and I've achieved that but seem to reduced overall velocity now, which is frustrating to say the least.

[netsurferdude2]

5 shots is no good.

Off the top of my head:
Clean lower tube, polish hammer, clean valve, change valve spring, replace seals, clean pierce pin, enlarge transfer port, use dyna valve

[Jordan]

5 shots is no good.

Off the top of my head:
Clean lower tube, polish hammer, clean valve, change valve spring, replace seals, clean pierce pin, enlarge transfer port, use dyna valve

All done already.

🙂

Brand new hammer, mainspring, valve spring, Dynavalve, valve with ported passageways, enlarged the transfer port, enlarged bolt passageways. I even put wedgits in.

No baseline, most of those parts were missing when i got the KP.

[RAZRBAKK]

5 shots? Jeez, make em count.

[Jordan]

I probably get about 20ish, but most go about 15 feet.

[Spider!]

What kind of pierce do you have?

BretG used to advise that you want a tiny hole to "sip" the CO2. It kind of goes along with the various kinds of flow restrictions used on different markers.

You need to separate the reservoir of the 12g cartridge from the dump chamber with a restriction. Auto/self pierce pins tend to have large holes, which then feed directly to the Sheridan dump chamber.

[Jordan]

What kind of pierce do you have?

BretG used to advise that you want a tiny hole to "sip" the CO2. It kind of goes along with the various kinds of flow restrictions used on different markers.

You need to separate the reservoir of the 12g cartridge from the dump chamber with a restriction. Auto/self pierce pins tend to have large holes, which then feed directly to the Sheridan dump chamber.

Shoot to pierce Dynavalve.

I actually trimmed the pierce pin down a bit, it was getting stuck in the 12 gram. Looks fairly concentric.

[Spider!]

Sounds like the valve spring is too light for the setup. 2c

[Jordan]

Sounds like the valve spring is too light for the setup. 2c

Could be... it's from PPS, I didn't have an original one.

[BrickHaus]

I wish I had some insights for you. I typically am trying to make sheridans work on hpa, so its a more flow, more spring mentality. I was surprised to see your valve plugs you did to make yours efficient. If the pierce is too much, is it viable to to restrict the valves output if the pierce hole isnt working?

Tap the other 2 valve holes, plug, and drill the plug out smaller?

[Jordan]

I wish I had some insights for you. I typically am trying to make sheridans work on hpa, so its a more flow, more spring mentality. I was surprised to see your valve plugs you did to make yours efficient. If the pierce is too much, is it viable to to restrict the valves output if the pierce hole isnt working?

Tap the other 2 valve holes, plug, and drill the plug out smaller?

I think that's my problem too... I'm so used to trying to improve performance with HPA that I'm worried I overdid it. 🙂

I did scrounge up a red Cocker valve spring that I've trimmed to fit and just installed it... preliminary testing shows some better shot count, but it's getting too cold to really check properly at this point.

[Jordan]

Here's what the puncture size looks like.

[Spider!]

I'm not sure about KPs, but that is huge for a Sheridan pistol.

Even the old turbo valves created pressure sensitivity due to their high flow, but we used them more for bulk CO2 tanks.

[Jordan]

I'm not sure about KPs, but that is huge for a Sheridan pistol.

Really? How small is normal? This looks to roughly 0.035"ish. I think the shadowing in the picture makes it look bigger.

[gabe]

My sheridan pistols barely will pierce a 12 gram. Like just a little pinhole in the 12gram face is what I'll see. Normally takes 2-3 strikes to pierce. 25 shots per 12gram that way.

[Spider!]

Really? How small is normal?

A barely visible hole is still functional. That's when the piercing is iffy, so it's usually a little larger. It should be the point through the seal. Does the valve body have a cone on it that the pin travels through? That's a big dish around the hole.