Nelson Marker Concept

[Lane]

Hey guys, been working on this in my downtime and thought I'd put it out there to get some feedback, I used to be on MCB all the time back in the day when I played more. Project essentially started with the goal of making a compact nelson marker with a uni-body (single frame/body) meant to be run with 12 grams for a very compact setup, since then it's evolved quite a bit with different features being integrated into the body. I've gotten to the point where I'm pretty confident in this being a workable design with only two real machining concerns, the long air passage from the front of the marker frame to the valve and the 3" X 1/8" slitting saw required for the trigger group, but there's enough clearance for a good size tool holder so I'm not too worried about slitting the frame. Current and upcoming features I have on it are listed below. Another goal is to try and keep the majority of manufacturing requirements pretty simple, if I can get a lot of good features in a cheaper nelson marker I may be inclined to move this toward a prototype. Overall the main body is about 6.5 X 3 X 1.1"

Let me know what you think and I'm open to any feedback, thanks!

- Bore drop with Autococker threads
- Undercocking pump kit
- Integrated pump arm that runs partially through the body for support (not sold on this idea yet, may run it through the body then to a side saddle that can be fastened to the bolt)
- Vertical ASA with gas through frame
- Threaded valve body for tool-less disassembly
- AR-15 style grip frame (can fit slim style grips without the back tang)
- Sliding trigger
- Forward safety in front of the trigger frame
- Rail on top for mounting different feed options, red dot sights, etc.
- O-ring on velocity adjuster
- Rubber detent

[bellicose]

The threaded valve body looks fun. External velocity adjustment is what I want most on a Nelson.

[Jellyghost]

External Velocity Adjustment would be amazing, and I have no idea how that would work. Maybe change volume in the back chamber?

[Arthur]

Sick

[Alexndl]

Very nice compact platform

[Rusty Brass]

Looks nice. Expensive to get machined, but really nice. It'd be the Bentley of Nelson guns if you can make it happen. A worthy rival to the Gargoyle II.
Like you already called out that air passage might be a rough one to pull off. The slotting doesn't seem particularly problematic though.

[AnarchicArctic]

You had me at Nelson

[NONOBLITUS]

Sign me up. This looks like a great idea.

[SignOfZeta]

Where is the detent?

[Stilgar]

Looks dope!

I personally would forgo the rails. They are added complication in the machining process. There are lots of options for phantom or CCM/Spyder style feeds already.

Are you planning to use phantom internals?

[bellicose]

I didn't want to be rude, but this is what I was thinking as well. Rails are gross. XD

[RedLeaderSB]

I have several questions regarding Nelson’s in general.
1) extra threaded part in back cap to adjust valve spring tension?
2) sealing mechanism between power tune and TPC? Never seen it so probably not feasible?
3) more air thru frames/asa would be cool

Very cool design, from someone who looks at CAD all day.

[Lane]

The threaded valve body looks fun. External velocity adjustment is what I want most on a Nelson.

This is why I like other people seeing designs, that didn't even cross my mind while working through this haha. Velocity adjustment is still in the bolt but you raise a good point. Would want to narrow gap between the o-rings so someone couldn't chrono it then crank the valve forward a few turns in the field.

Looks nice. Expensive to get machined, but really nice. It'd be the Bentley of Nelson guns if you can make it happen. A worthy rival to the Gargoyle II.
Like you already called out that air passage might be a rough one to pull off. The slotting doesn't seem particularly problematic though.

Agreed, slotting is not too worrisome, there's enough room for an 1"-1/4 collet so it should be pretty stable. Machine cost, yeah the body is definitely the keystone on cost and going to a hardline might get that cost down, couple bucks in hardline fittings and tube vs pecking your way down 5.5" with a .136" drill. Granted there's no separate frame, ASA, pump kit adapter, etc. to machine and anodize so that's a plus.

Where is the detent?

Not shown yet, likely on the right side of the bore above the hardline fitting in the images below. I could probably hide it somewhere in the body but there's so much going on in there already it may get weird fitting it in.

Looks dope!

I personally would forgo the rails. They are added complication in the machining process. There are lots of options for phantom or CCM/Spyder style feeds already.

Are you planning to use phantom internals?

Rails are definitely debatable, If it was a breech drop phantom internals may be possible. With it being a bore drop it's not likely an option, maybe the hammer, power tube and valve components. In order to get the internals through a solid bore with no slit on the bottom I had to forgo the typical hammer style sear and that's what in part led to the sliding trigger with the sear being tripped beneath the bolt and not beneath the hammer like typical phantoms. However, it still retains the auto-pump capabilities which is a plus. And the sear is pushed out by the hammer spring as it's installed. This lets you fit it through the back but once install the sear should stay within the slotted frame to retain proper alignment.

I have several questions regarding Nelson’s in general.
1) extra threaded part in back cap to adjust valve spring tension?
2) sealing mechanism between power tune and TPC? Never seen it so probably not feasible?
3) more air thru frames/asa would be cool

Very cool design, from someone who looks at CAD all day.

External threads on the valve body are to install it into the main body rather then use a thumb screw. This keeps the main body shorter with a clean flat back where the valve threads in.

Oring on the TPC acts in the same manner that the nylon set screw does on the phantom, it keeps the TPC from moving with friction from the oring fit (no more nylon set screw). The Spyder Hammer uses the same approach and I think I saw somewhere on here people started cutting oring grooves on their phantom TPCs to no longer need a set screw.

As for looking at CAD all day, you and me both haha.

[Mr. Hick]

Nelsons are already well known for their less than ideal pump stroke. Could you do us a solid and find at least one more rail for that pump? 2 would be better than one, and a triangulated set up would be even more better. otherwise I love the innovation i see.

[Lane]

Here's some additional images with a hardline setup and side-cocking. I really don't mind the hardline on the side and to remove the valve you just need to unthread the back compression collar then there should be enough wiggle room in the hardline to disconnect it as you unthread the valve housing.

For side-cocking, with hardline on the one side your probably limited to reaching the bolt from one side only so my worry would be a higher risk of binding but if you double up your pump guides that should make it pretty stable so it may be less of an issue. Because of the additional clearance for the saddle I can't run the pump arm through the body like before without widening it further which I'd like to avoid.

Now the other option is to go to a breech drop like the CCI phantom and that could open up a few other options with using CCI parts. If I could get the stock hammer, bolt and TPC to work that would be very beneficial. It would also reduces the length of the body by about a 1/2" or so.

[Siress]

Well done! There are a few features that can be simplified without compromising functionality, such as the grip frame interface and whatever is going on with the bottom of the trigger guard area.

The community will lash you if you only put one pump arm, though. Get at least 2 in there, and considering getting creative to take out any remaining slop - they love that sort of thing to an illogical degree. (I am among them...)

I see you're already planning to add a detent. That's necessary.

Can you anchor the trigger return spring to the pump arm to make the return spring tension adjustable? https://www.mcmaster.com/97745A130/

I don't recognize those internals aside from the valve. The hammer body looks typical but that sear is looking goofy - modeling artifact? You are likely dramatically underestimating the cost to mfg those in low volume compared to making them compatible with parts already on the market. I don't know where you can get a bore drop nelson bolt, but I haven't looked either. Even if you just maintain compatibility with the TPC and Hammer, that will likely save you 10% the cost of the body itself. If you're making a custom valve cap, please put an internal o-ring grove to seal around the power tube...

O-ring around the bolt between feed hole and barrel threads?

I think a clam shell design would make a lot of sense for the body itself. Consider just a metal tube from barrel threads to valve body threads, ASA, airline, and everything else could be a plastic clam shell. I'd ditch the threads for the valve body, have it insert into the primary tube, airline is inserted into a protrusion on the valve body, and then a screw/pin goes through the edge of the valve body/tube to keep them securely retained. That will obviate the clocking issues threads pose with orienting the feed hole and airline tube. Another benefit of this is that you can add a low friction film where the trigger is going to contact the body, like acrylic adhesive backed UHMW film.

I don't know if you're already in mechanical engineering, but you've got the skill set for it. Really well done.

[Stilgar]

That was my concern with the internals as well.

Simple is better. Common parts are good.

[XEMON]

The hard line is not a deterrent ... it looks nice.

For the thread on teh back of the valve/slip on with thumb screw: Why not use a screw, but on the top?
If you remove the top rail from the body, now you have an anchor point if you want to add such rail.

This gets 2 bird, with 1 less thread ...

no rail = less machining (+can put it if you want it)
no thread on the valve body/body tube = less machining

Also, i realy like the look of the side cocking with the little adapter.