SpudFiles

Well, my very first time machine a entire gun, so to all these pro machinists out there, please be nice, but critics are appreciated.
I bought a pack of .40 blowgun darts and a aluminium barrel a while ago because I liked a pneu dart gun, the JM. The price was more than 2000$ obviously I was not going to pay for that.
It looked simple, my guess it's just a 12g co2 receiver, regulator then a hammer valve. So I took a 5cm dia nylon bar and milled it to a block, then milled slots/drilled holes to make the receiver, valve seal and hammer housing.
The valves stem is made out off aluminium, very happy with it, air tight seal at any pressure. Hammer also aluminium.
Everything worked fine, a loud bang when I release the hammer... But then the fail came: the darts doesn't even leave the barrel
I had no idea how that happened, the only explication I could thing of is the hammer is too weak and it's not delivering enough air.
However, I'm too tired to find out why, this was just a warm up to build a serious PCP anyway. When I get more money, I'd probably buy some brass/ aluminum bars and blocks. Any tips about machine these materials would be appreciated, as I'm still trying to find out how to left a fine finish surface and slots.

Take out the hammer, drill it out and fill it with a steel dowel or a trimmed down bolt. Or just make a steel hammer...There is always a way.

I've tried different hammers, springs. None worked. So carry on and I'll just leave it as a milestone on my airgun making history I mean anyway it's my entry in a totally different level...

Why not put a smaller barrel on it? I'm sure it will work great for airsoft or 177 or 22 pellets... looks really good, regardless. Impressive.

Exactly my thought, the power is definitely enough to propel an airsoft bb, not a pellet though.

Despite the performance flaws, that thing looks awesome!

I've actually been looking towards a similar project myself, but I was planning to just get a reciever milled to fit on my crosman 2240 that can accommodate darts

wyz2285 wrote:I had no idea how that happened, the only explication I could thing of is the hammer is too weak and it's not delivering enough air.

That sounds like the problem, too low dwell time. Pity.

Could you show the valvestem and seal and possibly the amount of travel it has?


I'd also like to know the thickness of the valvestem and the porting size.
Does the valvestemhead move into the elbow?
If it does I can imagine it's in the way of the flow..

I'm guessing increased flow along with dwell time might improove performance a lot.

The port size is 6.8mm...
The design is a standard hammer valve, I'm pretty sure not retarded version
What do you mean "Does the valvestemhead move into the elbow?"
Worked all day to get a decent wooden stock, now I'm all covered in dust and also suicidal just thinking about all the sanding I'll have to do tomorrow...
(BTW I made a barrel adapter, now I'm using a 6mm barrel, at least it shots something )

Retarded version... That made me LOL

Looks good. I'm assuming a groove will be cut in the stock to let the block lay flush and the trigger stick out?

Looks good. I'm assuming a groove will be cut in the stock to let the block lay flush and the trigger stick out?

At least that's the plan... Right now I don't know what I'm doing anymore

That's how I always work no plan at all, I just wing it!!

I feel like this gun would look sick with a suppressor, and now that you know how to make them...

I feel like this gun would look sick with a suppressor, and now that you know how to make them... Wink

It's kind obvious I wouldn't left that skinny barrel hang out like that

Good man!

Only missing a suppressor and proper paint,