Metadyne Thumper/Phoenix Redux

[Timefreak17]

Update: phoenix

So on a observation between my thumper and phoenix, I thought the barrel to breech was too tight for the spring to seat the barrel properly. Leaving a gap that air escapes behind the ball, and forces the barrel forward. The thumper has an oring seal that works very well for this. So took a little sand paper to the back of the barrel ball catch, and a little to the edge of the breech that the barrel ball catch slides over.

After some tweaking I found the phoenix was shooting 384, with the barrel being held in place. And 220 just letting the barrel go do it's thing.

So more adjustment on the velocity adjustment screw, I was getting 280's withe the barrel held back into the breech.

And getting anywhere from 240 to 274 letting the barrel do it's thing.

I believe that a stiffer rear barrel spring will give a more consistent shot fps. This would hold the barrel into the breech with more pressure. Thus allowing more air down the barrel before the barrel gets pushed forward enough to let air escape via the rear breech and nut area.

Also I trimmed the detents to points that worked well still.

Can not tell you break to shot ratio as I was using re-usable rounds.

My next move is stronger spring in the rear.

Thank you for your time, hope this helps some.
Any questions or ideas post I'm up.

[XEMON]

I made a custom gasket for mine, I need to do more testing and will eventually machine the breach to hold it in place.
A stiffer spring return will need a spring guide so it doesn't reflect to the side and get damaged.

[Timefreak17]

Custom gasket between the barrel slide and breech? I'm assuming attached to the breech non-moving side.
That is a pretty good move, to help the sealing issue... 🤔.

I haven't had a kink issue (lol) with my return spring yet, but I will heed your advice on a spring guide.

[XEMON]

Yes, the gasket on the fixed side so when the slide comes back is seats against it. I will need to machine a few things to make sure it has the proper clearance and stay in place.
I also bored the barrel holder/slider so the freak insert comes all the way back and the ball sits inside the control bore. It helps tremendously with breaks.

Making a spring guide is gonna be a bit more complicated than on a Sheridan for example, I want it fixed on the body and go all the way through the rear slide to support the spring the entire length. It all needs to be drilled perfectly aligned to not bind.

[capitalpaintball]

I know this is not going to go down well, Considering all the problems everyone has had but... i shot it today at stockclass and it performed great. No breaks, chrono'ed 275. Absolutely no issues.
I bought the phoenix on ebay this week. Its number 0035. It came from Idaho (same as metadyne) i took it apart and lubed it(it was dry inside) it seems the guns has had a few factory fixes, the feed is bored out so tubes fit fine, and the barrel looks re-cut.
there are definitely things i would have done differently if i was designing it.i was getting 18 shots to a 12gram,slightly worse then the Thumpers 20. And the feed could have been longer, like 12 balls. I miss the vert asa but a icd 12gram stock works great and you can hold the front of the frame and use the thumb paddles.

[RuleOfSines]

Did you take any pictures of it apart by chance? I’m interested to see what unannounced fixes they have put in place.

[capitalpaintball]

Not any from the piston and reg. Area. Is the detent block always raw?

[Timefreak17]

They really just killed the rear feed tube and left it un-anodized...ok. I feel that's a quick fix and a sharp edge for balls to hit while loading.

The detent block is a raw finish, but probably clear coat anodized.

[RuleOfSines]

I was wondering if there was enough metal on the feed to bore it out like that without making it too fragile.

[Timefreak17]

Phoenix update:
Replaced rear pump spring for a slightly stiffer spring, same diameter, but slightly longer and thicker wire.
Re-tapped the ac threads in the breech to allow my older ac barrels to work. Metadyne always has a weird thread issue with their ac threads size.
Definitely holds the breach tighter to the body.
Shooting field paint, using reds ac barrel with .687 back.


Was messing around with velocity again. Could not get consistent velocity for some odd reason. I had it before but now it was all over.
So tore it down to each part possible and found this problem.

The velocity adjustment piston was marred up and notched like shark teeth.
So the drilled air thru hole between the velocity adjustment piston and mav-3c valve had a aluminum burr in the piston housing. So Everytime I would adjust the velocity I would add a notch to the piston when I cocked the phoenix under pressure. Those notches would jam the piston movement as well. So one shot would be 250fps, 134fps, 220fps, 120fps, 105fps, 253fps.

So I fine sanded the piston back to smooth. I used a Dremel to de-burr and grind down the problem area in the piston area through the screw thru port.

Removed all shavings and re-grease the o-ring s and areas needed. Then put everything back together.

Velocity was 280, 276, 284, 289, 281, 277, 290, 284, 284.

I think I solved my phoenix. No breaks while shooting or in the breech.
Shot another 20 rounds just to see what happens, and just worked.

[Tippster]

What kind of grease did you use?

[Timefreak17]

Used planet eclipse grease at first, very light coat. Thought it was sticking a tad.

Wiped that and used slick grease, have to find the jar to tell ya the actual name. But comes in a pink container