Help with my old Nelspot 007

[CGPro856]

I am trying to get my old 007 that I bought in the 80's and played with for a few seasons before putting it away for 30 something years back up to speed (literally) for today's pump only stock class games. I have added a detent to stop the roll outs which were probably the main reason I put it away in the first place, but now I'm trying to get it shooting somewhere close to 280fps. I have tried a series of different springs sold for the Phantom. With a slightly stretched red (plus power) main spring and a reduced power green valve spring it will shoot 230-240 ish for 5 or six shots on a 12 gram and then lose speed each subsequent shot. I made sure the power tube isn't blocked or anything and the paint to barrel match on the paint I'm using now isn't actually all that bad but it is the stock 4 or so inch barrel. Side note, the efficiency seems to have gone down hill steeply as I passed the 210 fps range. Can I modify the power tube or replace it with something else to get more FPS and maybe gain efficiency? the current power tube has two holes about 1/8" dia. by the seat. I don't know the ID or see any numbers on the power tube.

Am I wasting my time? is this as good as it gets?

Chris P.

[Painthappy]

We can get that shooting better Chris... Here is your first stop: https://www.mcarterbrown.com/forum/p...ers-group-info

Read it all I suppose, but there is a section for "tuning for efficiency".

That valve aka power tube can be changed out to a larger size. I would also probably change out the green for the yellow spring (your light spring) and that should give you more FPS right away.

The next thing would be to change out that stock valve tube for a larger sized valve tube and many of us have extras kicking around so that shouldn't be a problem finding one.

[Painthappy]

The color codes on springs should be:

Yellow: Light
Green: Medium Light
Blue: Medium
Red: Heavy

[CGPro856]

I don’t currently have a yellow spring or a larger tube but am willing to purchase.

and after reading the linked post, I get most of it except for the spacer part. I don’t think I have any spacers in my setup and wouldn’t know where to put them.

[Painthappy]

Don't worry about the spacer, that just going the extra mile for efficiency. You can get a nylon spacer at Home Depot, they're usually too long so you then cut them down. These will then go into the asa. The section where you have the small spring and screw in the valve tube? In there. That will suck up any extra space that isn't needed, but as I said, not needed.

Since you're valve is too small and your rear spring too heavy, what's happening now is that the heavy small spring is closing the valve shut too soon and the small tube isn't letting enough air through in that short period of time to get your fps up.

I had a thought and the other major inefficiency part could be the paint you have or are using is just too damn small. So all the air is escaping around the ball and not enough pushing it out which will also really really kill your efficiency.

[CGPro856]

That all makes perfect sense. Hopefully someone will pop up with a softer spring and larger valve tube available for purchase.

[CGPro856]

It’s been a very long time and I don’t really remember what parts I swapped or didn’t swap on this thing but the ID of the power tube measures about .1535 so l’m thinking it’s not stock.

[Nish]

Let me see what I have for tubes. You can also call Extreme Velocity and see if they are still selling the Nelspot length tubes that CCI used to offer.

[rathbaster]

I recently finished putting together a Nelspot for use
I simply replaced the internals with Phantom internals

Bacci Explains how to do that here

https://www.youtube.com/watch?v=SeewvQ01CwU

I haven't chronoed it yet but I've done this in the past and successfully created Nelspots that shot at the desired velocity (and are velocity adjustable)