tyronejk's POP 2026 build

[tyronejk]

Today's update:
My first attempt to make this wooden semi-circle started with a couple 2x4s screwed together and chucked in the lathe. This was both sketchy and looked like it was gonna take longer to cut than starting off with round stock.

So I switched to round stock that was way oversize and cut it way down.

And then cut to length and wood-glued it in place.

Next step would be cutting the top flat to have a mounting surface for the scope mounts.

[tyronejk]

I made some more progress this weekend. I cut and sanded this rod flat on top:


And then machined a plate to hold the trigger pivot and another to hold the valve assembly:




But now am finding out that space is becoming very limited. I may have to cut this wood back out and replace it with a thin aluminum plate to free up some interior volume to run hoses. As it sits, macroline can't squeeze through channel running fore-aft under this wood semi-circle.

[tyronejk]

Update: I got the main valve body and core machined today. I still need to drill threaded ports for hose barbs and cross drill a pin hole in the valve core to connect to the trigger mechanism.

[tyronejk]

I made a lot of progress today. First, relocating the hose barb on the VASA


Then drilled mounting holes for the scope mount:

And re-gluing this section of wood filler piece. The larger previous section popped out (who would've thought wood glue doesn't stick to polyurethane coating?) But this was fortunate since it gave me a chance to re-organize the hose routing.

And finally got everything mounted up

[tyronejk]

Now, I'm having a weird issue where when the trigger/valve is activated, the bolt stutters forward in two distinct stages. I definitely could use a QEV here since the exhaust route is very long, but I don't think this is the cause. I assume this will be easy to short stroke and have low ROF, but I don't expect the stuttering. Any ideas? This has a gen2 core, so it has many orings.

edit: maybe it is a slow exhaust flow causing this issue. I'll test again with a gen1 core I have lying around.

edit2: After testing with a known good Ion core, I think this is an issue with exhaust flow. I think the bolt starts moving forward when the air sear pressure drops to a certain amount, but the bolt moving forward compresses the air sear volume enough to increase the sear pressure and slow the bolt again, causing the stutter.

The right way to fix this would be adding a QEV but I don't have enough budget remaining to buy one. I had one from my Promaster project somewhere but it must have gotten lost when moving houses. Another option would be restricting flow further, but upstream closer to the sear itself and not way downstream by the trigger valve. Either way, I'll have to machine a flow restrictor or QEV from scratch, so that will likely be the next piece of work.

[tyronejk]

The flow restriction worked semi-successfully. I made this tube to hold two barb fittings and some kind of restrictor in the middle.

Initially testing with the largest ball bearing that would fit resulted in a comically slow bolt (but no stuttering)
https://youtu.be/e0_2hnZMzMg

Then I machined a more reasonable restrictor:

Which was a little better but still too slow:
https://youtube.com/shorts/s3ntNvCpe8U

So it looks like I do need a QEV but then realized I can just shift the body rearward closer to the valve. I think it'll work but will find out for sure next time.

[tyronejk]

And done!


JoeSchitt had QEVs for sale that just barely fit into my budget and let me complete this. The trigger itself is the original Enmey trigger but with an overly complex linkage to the valve. I did not design this well. It's a pain in the ass to assemble but it's working (on compressed air via remote line). I'll have to test it with a 12g and get a video.

[tyronejk]

I did a final test with a 12g and without velocity adjust (felt hot), I got 12 shots. Seems right, compared to more efficient Phantoms.