BB gun finally getting built!

[Mitchza89]

Haha thanks alot mate. Means alot coming from the All Mighty Jack!

[jackssmirkingrevenge]

I'll reserve further comment until I see it working

[Mitchza89]

Haha you and me both. It's getting pretty close to being finished. The epoxy has fully cured on the barrel and I've only got 2 parts to get, a ball valve and a brass bend. I'm actually surprised how well the epoxy piston came along. It should work really well but untill I'm able to rip a lead slug through a tree, I won't know

[Mitchza89]

Sorry for the double post but ehhhhh I had too.. Looks like im gonna be changing the design. The barrel just didn't hold in the end cap.. There is way too much play in it and it caused the epoxy to break Now I'm just gonna go for an external chamber. Argh this is so bloody disappointing. I need to learn how to solder and braise

Least I didn't lose any parts while making this gun. Thats the only possitive I can see...

[jackssmirkingrevenge]

You can try making up for the play by wrapping it tightly in masking tape, or cutting a snug-fitting wooden endcap out of ply like in this thread - you'd need several discs of 1/2" ply to make sure it's up for the pressure.

[Mitchza89]

No point. The barrel has slid completely out of the epoxy. But good ol' me has thought of a new idea. I'm gonna have the barrel seperate to the chamber so I can make the barrel have a bolt action breech. I used to fire these homemade darts when my bb barrel was sleeved in my marble gun. These things fly dead straight and they just keep on going. I'm not too sure how they will go at 300psi though.

Thanks alot for the idea though mate.

[jackssmirkingrevenge]

I think it's worth a try, have a look:

[MrCrowley]

Sorry for the double post but ehhhhh I had too.. Looks like im gonna be changing the design. The barrel just didn't hold in the end cap.. There is way too much play in it and it caused the epoxy to break Now I'm just gonna go for an external chamber. Argh this is so bloody disappointing. I need to learn how to solder and braise

Least I didn't lose any parts while making this gun. Thats the only possitive I can see...

Drop into an automotive or engineering shop and ask them to braise it for you, I got two FE tanks welded for $20 which is like $12US, and that's because the guy had no idea how much to charge me so he kept it to a round number considering I only had a $20 and I was more then happy to pay that.

[Mitchza89]

Hmm that is a pretty good idea. It just gonna be hard to use that idea because of the barrel was epoxied into the 3/4in compression fitting. By the time the copper chamber is through the nilon ring on the comp fitting, there isn't a whole lot of room to work with.

EDIT: Yeah MrCrowley I was definately concidering that but I don't know of many or any places around me that would do it. So you can get it done at any automotive shop ya reckon?

[MrCrowley]

Yeah I just yellow-paged/internet searched for one near me and I came across brugar engineering which specialises in mag wheel welding(to fix them up). I made sure they would do welding for me and rang first, I don't want to turn up like some dip shit at a random car shop asking for welding when they don't do it.

[Mitchza89]

Haha yeah thats it hey. I might even get a Mapgas bottle myself from my hardware shop and do it myself. I could use the experience but then again....I don't wanna stuff up my job

[MrCrowley]

There is a how-to on soldering some where on SF, you should look for it, I'm planning actually something very similar to this at the moment and would like to solder some fittings instead of epoxy them.

[Mitchza89]

Great minds think alike....as do crazy ones I'm just sick of forking out for epoxy and never have it work for me. Everytime I've had a spudgun go wrong, it has been because of epoxy.

So whats the specs on the gun your building at the moment?

[MrCrowley]

After seeing this, i'm gonna go copper over galv because it looks better and smoother, small-ish chamber about 1' long, 3/4" or 1" diameter, planning on shooting .2g metal BB's and with a 80cm barrel and 130psi or something I should have a muzzle velocity greater then 330m/s, i'm also mounting it on a stock I have with either a scope or red dot. Oh yeah its a co-ax btw

[Mitchza89]

That sounds really good dude. Only thing that stopped me for going for gal as the coax chamber, was just it's roughness inside. How ya gonna fix that problem?