Rear velocity adjusters on Nelson clones?

[The Inflicted]

Is there a reason you don't see more Nelson clones with rear velocity adjusters? It seems to me it would be fairly easy to design a rear valve body with a pair of O-rings on a threaded spring perch for the valve spring that would allow one to adjust the velocity by changing the force of the valve spring, not unlike the front velocity adjusters on a sentinel or Illusion pump. I would think at a minimum this would be an appealing aftermarket upgrade part for Phantoms. Is there a reason, aside from cost, no one's ever tried this?

[Jonnydread]

I feel like I have seen this before, but I cannot for the life of me remembering where. This would be a great mod to something like a Tigershark that doesn't have any easy way to adjust velocity via the bolt/hammer.

[The Inflicted]

I feel like I have seen this before, but I cannot for the life of me remembering where. This would be a great mod to something like a Tigershark that doesn't have any easy way to adjust velocity via the bolt/hammer.

Possibly, but I would think with a rear velocity screw you're more or less committed to having the valve body side-tapped or undertapped for bottomline use, which on a Tigershark isn't the easiest thing to rig up, at least not compared to a Nelson that can take a .45 grip block.

[Jonnydread]

Very true, but I wouldn't feel bad about destroying a Tigershark in the name of science, whereas on a Phantom I would.

[Ecapnation]

Because most Nelson's were back bottle which would require you to remove.ypur tank which would be silly/annoying to do to tweak velocity.

I have a custom phantom with a rear adjustment back.bottle asa and it's not only huge but thd adjustability of it is at best 20 fps

[The Inflicted]

Because most Nelson's were back bottle which would require you to remove.ypur tank which would be silly/annoying to do to tweak velocity.

Originally, yes, but it's been about three decades since anyone with a Nelson actually wanted to run a Nelson on backbottle by choice.
What with all the higher-end designer Nelsons over the years from LAPCO, RTR, and Carter, none of which even contemplate backbottle, I just wonder why no one made the leap.
The ICD PRP, for instance, would have seemed to be the perfect opportunity for this sort of thing to be implemented.

[Ecapnation]

Because during peak nelson days back bottle was the norm.... Nobody is improving them now it's just copy paste existing proven designs.

[Nish]

The back of the RTR cable is actually ASA threaded. That'd said you could probably rig something like what you are talking about up for that valve using a reducer that screws into the back and a sealed screw or making a valve insert that included an oring at one end to seal it off.

[Grendel]

Yup the back bottle situation for sure was a limiting reason and even if it is not back bottle you have to remember that the valve area on a Nelson (unlike stack tube markers) is pressurized. I am sure Ecapnation had to solve that issue with his customer Phantom valve body in the image above as well. For ease of adjusting velocity you need to not have too many "knobs" to twist so in the case of a Nelson style marker down the barrel for adjustment is just simpler and I expect because of spring length is more adjustable. The other way is to just add an inline regulator, spring marker to a compromise then use the regulator to fine adjust velocity. That is basically how I handled my Phantom with a sideline regulator.

[The Inflicted]

Yup the back bottle situation for sure was a limiting reason and even if it is not back bottle you have to remember that the valve area on a Nelson (unlike stack tube markers) is pressurized.

In what way is the valve on stacked-tube marker not pressurized?

[Grendel]

I guess I was not clear you are talking about the back of the marker doing an adjustment from the back and on a nelson that is the valve and on a stacked tube that is the hammer section. Where velocity adjustment is made on a stacked tube is not pressurized it is the hammer spring section just like with a Nelson you adjust the spring that is not the valve spring. You do not adjust the velocity in a stacked tube marker by adjusting the valve spring you adjust the Hammer spring just like in a Nelson.

[The Inflicted]

"You do not adjust the velocity in a stacked tube marker by adjusting the valve spring you adjust the Hammer spring just like in a Nelson."

...except on the Action Markers guns you do. That's why I mentioned them.

[Jackson]

True Nelson compatible valves are mounted via a screw straight down completely through the valve from the top on centerline. Even without a back bottle valve, this is an obstacle that would need to be addressed. Phantom valves are mounted via a screw from the bottom. Which is why Ecapnation's valve is possible. The end of the thread doesn't reach the axial center.

[The Inflicted]

True Nelson compatible valves are mounted via a screw straight down completely through the valve from the top on centerline. Even without a back bottle valve, this is an obstacle that would need to be addressed. Phantom valves are mounted via a screw from the bottom. Which is why Ecapnation's valve is possible. The end of the thread doesn't reach the axial center.

Not just the Phantom, pretty much any Nelson-derived gun made in the last 30-years (Hammers, Diablos, Traccers AND the Traccer revival, the PRP, etc.) has used a bottom-oriented valve retention screw rather than one that runs top-to-bottom. The only real exception was the LAPCO Ghost remake.

[Morgenstern]

I thought about this a lot and you would be adding a component which would be the most likely thing on the whole gun to fail (leak from o-ring that moves during adjustment) for minimal gain. But, if it were a standard bottle o-ring that allowed the RVA to seal it would be easy to replace and hey, folks replace bullet proof basic ASAs with on/offs that end up leaking all of the time, so maybe people wouldn’t care? It would be kind of neat

[capitalpaintball]

Cooper T made and sold a back bottle adapter for nelsons with a velocity adjuster. had one on my Bushmaster. Problem is I dont think the valve spring really changes the velocity all that much.