E99 build and test thread

[RhoXi]

3/22/25 Roll Back Prevention

I had an idea while messing with the venturi last week. I thought how could I prevent the ball from rolling so far back into the bolt face? Then I thought what if the venturi was longer? So I got the idea to drill a hole in the front of the venturi and then thread it to accecpt a rod or bolt long enough to be flush with the bolt face.

After a trip to the hardware store, I ended up with a 10-24 x 2 socket head bolt and a M6x1.0 x 75 shouldered hex bolt. I wanted to try the idea with the socket head screw first in order to keep the venturi in the mix. I drilled and tapped (poorly) the front of the venturi and cut the bolt down to size till it was flush with the bolt face while installed.

It looked good but unfortunately that didn't cure my ills. I shot a few and velocity looked similar to last time. So far so good. Then I decided to shoot a long string as fast as possible and that's when it chopped at about 20 or so shots in. A definite stack clip as there was paint in the breech and feedneck.

Back to the drawing board but for now here's some pictures of my handywork.

[Kit352]

The micro switch on those are just normal 100g ones with the little metal flap removed. You can get lighter triggering ones if you wanted but they get touchy if you go to low. I think 25g is as low as you want to go.

[RhoXi]

Ah word thanks!

[MrKittyCatMeowFace]

If the paint is too small/oblong, you will continue to get stack clipping. Not using a force fed loader helps too. With 10bps being pretty much the standard now, non force fed loaders can keep up fine for the moist pork.

[RhoXi]

Lol that's a heck of a typo.

I've been using my Vmax+ becuase my Revvy wasn't keeping up when it double fires. Or at least I thought so. I'll give it a shot again next time. And yeah, this paint is small and not very round but such is the way of paintball in 2025.

[William the Third]

[flyweightnate]

I would try adding something soft to the face of that anti rollback bolt - like a cabinet door bumper or a mechanical pencil eraser. Steel is unforgiving.

Also, chamfering the top edge (like the Ego Cure bolts) might give you some blowback up the stack, but also might keep you from clipping that second ball.

On a lot of these, you have a .700" breech holding a .670 ball, so there's plenty of room to hit the next ball in line.

[RhoXi]

3/28/25 Sanity Check

I had a thought today that I should figure out weather or not it's the Spyder that's causing my my chopping issues or the paint. So this evening I loaded up my Promaster (which is normally pretty good with paint) and let it rip. To my surprise I got a chop about 20 or so balls in, just like the Spyder. Huh. So I went and got my Shocker NXT which should also be pretty gentle. Same exact thing. Chop about 20 or so balls in. Alright, so I then grabbed the Phantom. It should be to no one's surprise that the last 50 or so paintballs in the bag went down range without incident (Not totally true. The Phantom was struggling to seal up on 12g's for some reason so I had to switch to hpa. No chops though.)

I'm thinking these paintballs are just small enough and out of round enough that's it's just too much for my autoloaders to handle. Visually, they're not the most oblong paintballs I've ever seen but they're certainly not perfect. That combined with the smallness is just enough to cause stack clipping and headaches. I think I'm going to hold off on trying to improve paint handling much more untill I get some better paintballs. Still, I might throw down some numbers with the anti-rollback venturi mkII anyway but just single loading.

[nak81783]

I’m a little late to the party, but consider using nylon riot balls like I used in the first link below to take paint variation out of the equation for your velocity testing.

Also, do Spyders have the same issue as Azodins where the ball is shot into the barrel, rather than being pushed into it by the bolt prior to the air blast being released? See second link below for some pics and info of what I did to remedy that. Someone else posted some better pics which show the issue of an Azodin pump with the barrel removed and a ball sitting too far back in the breech with the bolt forward.

https://www.mcarterbrown.com/forum/p...s-rate-of-fire

https://www.mcarterbrown.com/forum/c...zodin-kd3-pump

[RhoXi]

I do have some reusable paintballs lying around but I've only used them for function checking. Originally, I was just trying to hit field velocity and the re-balls I have shoot about 30-40fps faster than paintballs. I think I'll have to revisit them after reading through your testing (good stuff btw).

And no, Spyders don't have the same problems as Azodins. The barrel butts right up right where the bolt travel ends inside the breech like most 'cocker threaded guns.

[RhoXi]

4/10/25 Back at it

I had to take a little break and did some more research. I managed to find the old Otter's Customs page on the way back machine and it convinced me I probably do need a secondary regulator in the mix. Went to the old parts box and dug out a Trillogy Pro reg I had and slapped this together.


This giant drop-forward it the only spyder pattern asa I have lol. Before airing it up, I backed out the reg adjuster a bit and took some shots.

All other parts are the same as before except for my anti-rollback venturi v2. Velocity adjuster about halfway in.

305, 295, 295, 295, 301, 296, 298, 290, 301, 297
Average: 297.3
Standard Deviation: 3.98
Spread: 15

Thoughts: Really good results for just throwing some stuff togeher. It's interesting to note that I am getting similar velocity with less spring tention with the Trilogy reg than without. I am definitely going to be on the hunt for an externally adjustable reg with a gauge port now to really get this dialed in. I would love to be able to use a lighter drive spring as well. More details about the venturi buisness in the next post.

[RhoXi]

Anti-rollback venturi v2

This is somewhat of a refinement of my earlier idea. Basically I chopped down a stainless hex bolt to length then chucked it up in my drill and rounded off the hex part then cut a slot so I could get it out again. I found some small rubber discs that happedlned to be the right size and glued one to the head of the bolt.

It looked good at first but testing didn't go so well. I shot a couple handfulls using a gravity hopper with no chops. However, using the Vmax once again made the gun a blender. Back to the drawing board.

[Kit352]

An ans gen 2 reg would work well and is sort of period correct.
Have you tried any of the aftermarket bolts yet just to see the difference? You may find that trying to mess with the stock one just isn't worth the $10 a new one costs.

[RhoXi]

At first, I did consider getting a bolt but decided against it for some reason. Maybe I thought it'd be easy to get the stock one working. Definitely going to be looking into it now.

[RhoXi]

4/21/25 Dual Detents

This is an idea I've been thinking about for a long time. I've noticed that sometimes after a chop and I remove the barrel, there'll be a ball halfway fed past the detent. I believe this is the source of my chopping woes. So today I finally got up the courage to put the body under the knif-, um, drill press. Using the existing detent hole as a guide, I used a 25/64 bit to drill the hole for the detent. Then I flipped it over and used a #30 bit to make the hole for the screw. I tapped it for M4x0.7 and installed the second detent.
Top view
Full view
Borrowed the Stabilizer from my Trilogy for tuning purposes and threw on this mangled on/off and Shocktech 0 rail after getting a Kingman to Standard adapter. Also picked up a sweet Lapco Autospirit to replace the stock barrel.

I ran about half a hopper through it in this configuration on full auto and had zero chops. Excellent. I'll need to tweak some more but this result is promising. I'll update once I settle on a final configuration but it's pretty dang close as it is.

[Kit352]

I think dual detents for older spyders are almost mandatory at this point. Today's balls are just too small. They make different durometer nubbins too but I haven't tried any of those yet. I've just been using the small black ones.
Have you thought about enlarging the air passage holes in the front block?

[RhoXi]

I have but going off Otter's LP spyder guide my passages are already the right size and there's not much meat left to drill out. ANS has a Taso low pressure front block for cheap that I might give a whirl.

[Tarsun2]

i think Kingman saw the future and put dual detents on some of their old markers. lol i forget which ones though.

[RhoXi]

I think you're right. If memory serves me right, it was the Pilot ACS that first came standard with dual detents. I believe it was one of it's big marketing points too lol.

[RhoXi]

*cough* Pretty dusty in here...

I've finally come back around to this project. It got shelved while waiting for some parts then forgotten about. I finally got the last couple of parts this past week so here's how it sits:
-Stock bolt, no venturi
-Dual detents added
-modified EKO valve
-warrior springs; black valve spring, silver drive spring
-Azodin feather striker
-Taso "low pressure" front block
-Air America Vigilante
-Lapco Autospirit barrel

Right now I am getting mid 290's fps with generic re-balls at ~500-525psi with the velocity adjuster all of the way out. It cylces fine on re-balls but will not re-cock while dry firing.

Shot quality wise, it's very nice for a blowback but I'd like to go to the black (light) drive spring with the hopes of being able to pinch a paintball instead of chopping. Right now I'm looking into filling hole in the bottom of the body as I've heard that's what some people have done when persuing low pressure but I'm not sure if that'll let me use a lighter drive spring. Going that route will increase blowback pressure which might be counterproductive to my goals but would allow lower preasure. Or a full-weight striker might allow the light drive spring but it might compromise the shot quality. This requires more thought.

The Vigilante is a nice companion for this build I think. It came to me with a bad reg seat and was a big part of what held the build up. I searched for a good long time for a replacement till I finally gave it a closer look. Turns out an Automag reg seat works perfectly.

I'm hoping to pick up some paint in the next couple of weeks to tune this thing properly so I can hit the field with it this year.