Open bolt pumps

[downfall]

So here are two ideas, they are pretty simple to explain without a picture, both designs use a two lug hammer, one lug for the pump arm and one trigger.

One: An autococker-style hammer/ivg striking a valve that goes into an automag style bolt

Two: A (pull instead of push) power tube with a bolt as hammer

Will one have too much mechanical delay before firing?

Will two be too difficult to adjust the velocity? I am thinking the power tube will have to be in two parts.

[iamthelazerviking]

Pump Emeks have been created, which would technically be an open bolt pump, however they operate more as a "slamfire" where it fires just based off pump stroke and not pulling trigger

[Ecapnation]

I've not seen this either

[iamthelazerviking]

Dunno if y'all will be able to view or not.

https://www.facebook.com/share/v/mdc9Xt8DavsvoM2c/?mibextid=oFDknk

[William the Third]

iamthelazerviking yeah I wasn't able to see it (no Facebook account). Definitely very curious about this though.

[Grendel]

Why open bolt pump? Do you see an advantage over a closed bolt pump? Open bolt really was an advantage for the speed wars as far as I can tell. I have an open bolt pump, a pump Automag and honestly it does not get much love because it really has no advantage over my standard closed bolt pumps. The only thing I can think of as an 'advantage' is in an open bolt pump you can rely on the ball detent to keep from double feeding our variable sized paint vs. using some form of barrel sizer/sizing or wedgits to hold the ball in the correct space in the bore.

[downfall]

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)

[Magageddon]

I will say I do see a slight advantage to this with having shot my pump mag a lot. Mine has a pump milled ule body though. I never get roll outs because the detent protrudes far enough to keep the ball in the breach area, but being open the bolt doesnt push the paint forward till I take a shot.

I think OP should try a pump mag

[downfall]

I would love to try a pump mag!

Would I also want a pump marker with autotrigger and gas through trigger frame, you bet!

[iamthelazerviking]

The new Nova pump can be switched to semi auto instantaneously but also has a lock to prevent it, making it pump tournament legal. Not sure if it's open or closed bolt though

[markdem]

I use an open bolt pump frequently.

Open bolts have a slightly delayed firing cycle but its not a problem.

And no, velocity wont be hard to adjust

You should upload a sketch of your idea

[downfall]

[markdem]

Both ideas could work. Worth a try. Even if they dont work, it'll be a great learning experience.

If you have the space (and the funds) you should buy a small lathe with thread-cutting capabilities and start machining your ideas into reality.

[downfall]

I don't know how regulators work yet or what makes a good one so that's the first hurdle.

I would probably use Xometry or something for manufacturing

[markdem]

Your designs appear to be poppet valves which will work without a regulator.

Your first hurdle is coming up with a schematic. Doesnt need to be fancy, but it must be clear and well thought out

Again, i suggest buying a manual lathe because you can make adjustments on the fly. Plus, you dont need to learn fancy CAD software. Attached picture of what a clear, well designed schematic should look like

Also, check out some spud gun and air gun forums. They have lots of designs and techniques that are geared towards people without lathes

[downfall]

I've worked briefly with manual mills and cnc mills so I am somewhat familiar with gcode etc. I don't remember the physics of springs too well for that matter so that might take some time to get distances right.

I am familiar with Fusion and Alias so no problems there

Correct me if I am wrong, I am new to the terminology, but 2 is a spool valve? it looks like a 3-way. 1 is a black box. I haven't decided how the valves are yet.

[downfall]

Oh and which would you rather have? 1 has a sliding trigger and more mechanical delay

[markdem]

I personally love overly complicated contraptions. The more janky - the better

Youll have to decide which is best. Go with what makes you happy, not with what other people think is "good"

[markdem]

Now that i zoom in to the image, you are correct. #2 is a spool valve

If you have the skills to design 3d cad stuff, do so. Please keep us updated. Would love to see more!