Open bolt pumps

[autococker04]

I dug through PBN for so long looking for this monstrosity I built in high school. Fortunately I wasn’t able to find the shooting video I had at one time, that probably means no one else can either. Easiest route to an open bolt pump, the only thing hard to get was the wave spring. Basically a wgp pump kit with a piece of sanded and bent threaded rod, held to the gun with a chunk of aluminum from metal shop. The body and tail were already pump milled

[SignOfZeta]

Objectively good paint is harder to find, I distinctly remember sizing paint and either having rollouts anyway or breaks from balls that ran big after sizing.

So I wouldn't have fun bc I was either wasting 12 shots to hit an exposed part due to a barrel break, or having a rollout.

Subjectively I just realized that I enjoyed my open bolt markers more (Angel CNC, A-5) more than my closed bolt (ICD PRP, Works cocker, Excalibur)

This is silly. I literally only play with closed bolt pumps and I have like one rollout a year and I basically never have breaks. What you do is put some sort of detent in the barrel, which can be as simple as a small piece of black tape, and then the problem is gone. The solution isn’t to design a brand new kind of gun that fires late on purpose.

I appreciate a great deal of the creativity around here but I’d say a full 1/3 of the projects are trying to fix a skill issue with ultra niche gear nobody needs. Try learning how to shoot better instead of blaming 50 year old designs that are used daily by 1000s of people without issue.

“I just can’t hit the broad side of a barn unless it’s a positive feed side saddle undercocker with an 86 grip” is another way of saying you suck at paintball. If you were good you’d be able to hit that barn with any gun that’s accurate. Barns are pretty big and where the CO2 enters the gun doesn’t matter. Grip angle doesn’t matter. Bolt position doesn’t matter.

[SignOfZeta]

Ha! I meant to say I only play with CLOSED bolt guns. I think that whole thing probably makes more sense now.

[downfall]

Did you mean that you exclusively play with closed bolt pumps?

Where do you live? Maybe your paint has been heat cycled less for instance.

As far as how late the gun fires it is twice as late as some guns, but the same for design two. Really idk, even closed bolt guns have to wait on the hammer etc

On the flip side (about bolt position not mattering) name one (non-pump) tournament gun that is closed bolt being used today.

[Myrkul]

I have a few friends who have run Nova N4s in mech tournaments. No idea how competitive they are with them, or what the skill level of the tournament was, but it has happened. So there is a closed bolt in a tournament.

[downfall]

I guess I could just use an Empire Axe on/off reg and work with design two

[Funsi00]

Pump ion fall under open bolt pump?

[downfall]

I wasn't completely sure but yes they are

https://www.pbnation.com/showthread.php?p=82118913#post82118913

[downfall]

I have a few questions if anyone is able to answer:

What is the gap between the breech and sliding parts? Static pressurized parts?

Are desktop cnc's sufficient for machining paintball marker parts? (Pocket NC (5 axis), Samurai 120H, Shariff DMC2) although most shops seem to use 4axis

[markdem]

Gap? Sliding parts? Youll have to be more specific. What style of gun are you talking about?

Sorry i have no experience with cnc

[downfall]

If my bore is .700 should my bolt also be .700?

[downfall]

Sneak peek (I haven't decided on the feedbeck at all)

The detent is going to be from below like an A5.

The PRP had a good pump handle.

And if you're curious, the A/T is currently done with a cylinder cam, after wasting hours with a gearbox... lol

[markdem]

Coming along nicely, my friend! Super interested to see the inner workings!

excellent design. Good planning. Keep up the good work.

For the feed, i would consider making it adaptable between open/stock class

[KMDPB]

This maybe somewhat unrelated but I think the splatmaster is a super cool open bolt design. I'd like to make a more modern paint gun using the splatmaster design

[markdem]

Excellent point! How could we forget such a classic?

[downfall]

Progress report, some of the parts ended up quite small/high tolerance. This is my first major project with CAD so wish me luck!

[markdem]

Good job! I wish i knew how to use cad. Would be so handy for seeing how moving parts interact with each other

I can see you still have some work to do. Keep up the good work and keep trying until you have a functioning design

[downfall]

I am sure you could imagine a sculpting based approach, I sure can.

Really if you can draw you can use CAD, although somethings to be aware of are the curve representations because they are not equal. Some programs have more control points in their curve definitions which means you get more curve continuity G0,G1,G2 https://www.aliasworkbench.com/theor...ontinuity1.htm

In our application space CAD is an additive an mathematical approach to creating objects from points, lines, planes, and volumes (which are tesselated for display). Their relationships are defined with eachother to create more complex shapes.

Some things are easy to visualize but hard to create in CAD, and that is just a thing of experience. For example to cut a groove for the cylinder cam which is simple to visualize requires me to either make/download a bespoke tool or to construct a spiral around the cam and then use an intersecting line as a guide rail to sweep a face, which means i am limited in the angular rate (in that it would be constant)