Homemade PCP receiver

[bsahogger]

Also started with the pistol grip attachment. I decided to go with the ubiquitous AR style, there's a million pistol grips to choose from, you're bound to find one that suits you perfectly. Saves me quite a bit fab time!

 

[bsahogger]

Trigger guard & pistol grip attached. I have left some meat in the trigger guard since I'm at a crossroad now: I have to decide whether I'm fitting this with the solenoid hammer or going with a conventional spring loaded system. If I go with the former I'll need space for some micro switches. I've also been pondering some safety issues: the heavier I make the solenoid hammer the more likely the gun would be able to fire if shook in the vertical position, especially with the barrel pointing down (the springs holding the solenoid cores back are super weak by design). So I'll probably run a pin vertically through the front of the trigger guard all the way up to the tip of the hammer: this pin will block the hammer, it can only be pulled down by the trigger.

 

[Scotchmo]

The the Solenoid City plunger is only about 40 grams. And your stroke will be 1/8” to 1/2”. It will be very unlikely that you could shake the gun hard/fast enough to have it pop the valve open. Maybe if you drop the gun muzzle first from 10 feet off the ground.

Running 18v directly into your low resistance solenoid will behave differently. Longer stroke will give more hammer energy. If you go with a capacitor discharge, increasing the stroke beyond a certain point will reduce the hammer energy, as the capacitor voltage falls off while energizing the solenoid through such a long stroke.

The electronic hammer has a big advantage when designing a trigger. It’s very simple compared to a mechanical sear.

 

[bsahogger]

The solenoid plunger is only about 40 grams. And your stroke is 1/8” to 1/2”. It will be very unlikely that you could shake the gun hard/fast enough to have it pop the valve open. Maybe if you drop the gun muzzle first from 10 feet off the ground.

The electronic hammer has a big advantage when designing a trigger. It’s very simple compared to a mechanical sear.

Yeah we'll see how it goes. As I say I have the safety pin in mind, with that in place the gun can't fire when shaken or dropped no matter how heavy I make the hammer.

 

[Fly]

Great job my freind, I,m a retired tool & dye maker, & not going to pick your work a part by any means.
It,s about making it work & you did that.My problem in doing that, I still do not know that much about
the workings of these guns. I just like shooting them. I applaud you for jumping in & going for it. My only advice
buy a set of R8 collets for your vertical mill.

Fly

 

[bsahogger]

Great job my freind, I,m a retired tool & dye maker, & not going to pick your work a part by any means.
It,s about making it work & you did that.My problem in doing that, I still do not know that much about
the workings of these guns. I just like shooting them. I applaud you for jumping in & going for it. My only advice
buy a set of R8 collets for your vertical mill.

Fly

Yep, pragmatic approach, that's me, make chips, then think about how it's going to work
Believe it or not, I do have collets but as mentioned earlier I'm super lazy, takes way too long to swap collets if I'm spot drilling, then pilot drilling, then drilling to tap size, then tapping... so if I'm playing with aluminum I mostly just use the ol' drill chuck.

 

[bsahogger]

The the Solenoid City plunger is only about 40 grams. And your stroke will be 1/8” to 1/2”. It will be very unlikely that you could shake the gun hard/fast enough to have it pop the valve open. Maybe if you drop the gun muzzle first from 10 feet off the ground.

Running 18v directly into your low resistance solenoid will behave differently. Longer stroke will give more hammer energy. If you go with a capacitor discharge, increasing the stroke beyond a certain point will reduce the hammer energy, as the capacitor voltage falls off while energizing the solenoid through such a long stroke.

The electronic hammer has a big advantage when designing a trigger. It’s very simple compared to a mechanical sear.

"Running 18v directly into your low resistance solenoid will behave differently. Longer stroke will give more hammer energy. If you go with a capacitor discharge, increasing the stroke beyond a certain point will reduce the hammer energy, as the capacitor voltage falls off while energizing the solenoid through such a long stroke."
Makes a ton of sense, can't wait to have this thing assembled so that I can start playing with all the electronics variables, going to be super interesting. Think I've made up my mind, I'll go with the solenoid hammer for this build, next one I may do conventional spring hammer.

 

[sb327]

With a bit of creativity, you could probably make it convertible. Depending on what type of sear engagement you were planning for the spring hammer, you could maybe just flip it to be outside the bore and hit a micro.

Fwiw, for bench shooting and testing, a remote trigger works fine too.

Dave

 

[bsahogger]

The folding adapter for an AR stock came in so I turned a plug attachment for it & drilled/tapped some holes in the back of the receiver to accept that. Deciding now on what style AR stock I'll be using, once that comes in I'll be able to assemble this sucker & start shooting tests.

 

[sb327]

Where did you find that adapter?

Looks good!
Dave

 

[bsahogger]

Where did you find that adapter?

Looks good!
Dave

Amazon, freakin' spendy @ $150, most expensive part of the build so far. Next rev I may rather thread the back of the receiver to accept an AR buffer tube in order to save cost. Upside of this adapter though is I'm thinking of storing the batteries in the buffer tube, with it being able to flip open I can obviously access the batteries easily for replacement, maybe there's space in the there for the capacitor as well.

 

[sb327]

It’s nice looking for sure. I have used one from an AEA I have on some of my builds that’s pretty sturdy. It doesn’t look quite as good as the one you have but it’s a lot cheaper, just for future reference. They are a tad loose (I have 3 AEA’s) when you get them but the nub is threaded and loctited, it has some room to be tightened more, just heat up the loctite.

https://www.bintacllc.com/product-page/aea-airgun-folding-stock-adapter

Dave

 

[bsahogger]

It’s nice looking for sure. I have used one from an AEA I have on some of my builds that’s pretty sturdy. It doesn’t look quite as good as the one you have but it’s a lot cheaper, just for future reference. They are a tad loose (I have 3 AEA’s) when you get them but the nub is threaded and loctited, it has some room to be tightened more, just heat up the loctite.

https://www.bintacllc.com/product-page/aea-airgun-folding-stock-adapter

Dave

This sucker is very tight,I obviously don't have much leverage on it yet but I doubt it'll wiggle.

 

[bchannell]

This is so interesting to watch. You're doing a fantastic job and I can't wait to read each new episode. Keep up the good work and enjoy it!

 

[rodm1]

If this works out consider drawing up some blue prints. I'm interested in a set if you do at a fair price.

 

[bsahogger]

This is so interesting to watch. You're doing a fantastic job and I can't wait to read each new episode. Keep up the good work and enjoy it!

Thanks! Let's hope don't mess it up!

 

[Smitty911]

Didn't read the whole thing yet, but I will get to it.

Two items:
1. Before you tap those holes use a 100º cutter and deburr those holes. It will keep those ridges from coming up.
2. If you are thinking of going electronic - Order a Heliboard, that will give you all the electronics in a Known package.

Smitty

 

[almost sbd]

Thanks for sharing this project with us. Awesome !

 

[bsahogger]

Didn't read the whole thing yet, but I will get to it.

Two items:
1. Before you tap those holes use a 100º cutter and deburr those holes. It will keep those ridges from coming up.
2. If you are thinking of going electronic - Order a Heliboard, that will give you all the electronics in a Known package.

Smitty

Thanks for the help, much appreciated!!!

 

[Scotchmo]

Didn't read the whole thing yet, but I will get to it.

Two items:
1. Before you tap those holes use a 100º cutter and deburr those holes. It will keep those ridges from coming up.
2. If you are thinking of going electronic - Order a Heliboard, that will give you all the electronics in a Known package.

Smitty

That might work really well, but I think you’ll then need to add an appropriate pressure transducer to the plenum. But you can then get by without a regulator.