I've decided to revisit this idea, here's what I have so far, looks promising
[youtube][/youtube]
How's that for blowback took the ignitor right out of my fingers hehe
That was done with just a loose fiting marker cap as ammunition, there should be plenty of power to cycle a semi-automatic action. now to build the breech, watch this space.
Posted: Wed Jan 20, 2010 1:08 pm
by JDP12
hahah AWESOME JSR!!!!!!!!!
That'll definitely help me out with my project. I just need to get some glue!!!!
Congratulations on a great success.
However you may need to look into a better sealing method, you lost alot of pressure since the cartridge blew out before it even had a chance to fire--hence the massive fireball at the breech
Posted: Wed Jan 20, 2010 1:21 pm
by jackssmirkingrevenge
JDP12 wrote:However you may need to look into a better sealing method, you lost alot of pressure since the cartridge blew out before it even had a chance to fire--hence the massive fireball at the breech
The cartridge is an extremely good fit in the breech, naturally because it's cast around it. I wrapped some packaging tape to allow for a slightly greater cast but we're talking about one thickness of tape, I'm not worried about the seal. Consider that in the case of the above test there was absolutely nothing holding the cartridge or breech other than their own weight, and also the projectile was extremely light and loose fitting (about 0.74") - knew from my previous cartridges that there would be blowback and I didn't want it to be too powerful, this was more of an ignition test.
Building the breech as we speak, I'm hoping to have it done within the next few days. If that works well I'll add a magazine and see how that goes.
Posted: Wed Jan 20, 2010 1:24 pm
by JDP12
ah, very true. Good points...
Stupid glue!!
Posted: Wed Jan 20, 2010 1:53 pm
by potatoflinger
Can't wait to see it in action. How many shells are you planning on making?
Posted: Wed Jan 20, 2010 2:16 pm
by jackssmirkingrevenge
potatoflinger wrote:How many shells are you planning on making?
Since they're so big the stick magazine I'm planning won't hold more than 4-5 so probably not more than that.
Posted: Wed Jan 20, 2010 2:45 pm
by psycix
In that case go for 8-10 and be able to swap magazines.
Posted: Wed Jan 20, 2010 3:29 pm
by JDP12
very nice, i may just have to step up to a 1.25" shell and make a grenade launcher--
or what the heck screw pump action and just go with semiautomatic
Posted: Thu Jan 21, 2010 2:10 am
by jackssmirkingrevenge
psycix wrote:In that case go for 8-10 and be able to swap magazines.
I was thinking of a fixed magazine for the sake of simplicity.
or what the heck screw pump action and just go with semiautomatic
I think semi-auto through a straight blowback action is by far the easiest to achieve, pump action through an underbarrel tube magazine is a far more complex operation to undertake.
The basic breech is ready but I'm going to slop on a lot more epoxy tonight to make sure it's up to the strain, hopefully by the time I'm ready to test it my latest media purchase would have arrived and I can offer some high speed footage
Posted: Thu Jan 21, 2010 4:59 am
by Insomniac
jackssmirkingrevenge wrote:In that case go for 8-10 and be able to swap magazines. The basic breech is ready but I'm going to slop on a lot more epoxy tonight to make sure it's up to the strain, hopefully by the time I'm ready to test it my latest media purchase would have arrived and I can offer some high speed footage
I'm looking foward to it. I'm interested to see at what point the cartriage detaches, relative to the movement of various projectiles. Any chance of a transparent barrel to better see what's going on? Perhaps you could cast one out of epoxy
Posted: Thu Jan 21, 2010 6:15 am
by jackssmirkingrevenge
Insomniac wrote:Any chance of a transparent barrel to better see what's going on? Perhaps you could cast one out of epoxy
It's not impossible, I have cast tubes before but I have enough on my plate making the breech block for this thing at the moment. Tomorrow I should have it ready for testing, in the meantime I got a call saying my camera arrived at Customs so I should have it by this afternoon
Posted: Thu Jan 21, 2010 6:22 am
by Insomniac
jackssmirkingrevenge wrote:
Insomniac wrote:Any chance of a transparent barrel to better see what's going on? Perhaps you could cast one out of epoxy
It's not impossible, I have cast tubes before but I have enough on my plate making the breech block for this thing at the moment. Tomorrow I should have it ready for testing, in the meantime I got a call saying my camera arrived at Customs so I should have it by this afternoon
Sounds great! Mine arrived in the morning, right before school... so I had to sit through a full day of lessons before I finally got to try it, and then I had the long wait while the battery charged, which had the infuriating side-effect of it being too dark outside to film anything by the time I finally had it working
Posted: Thu Jan 21, 2010 8:25 am
by JDP12
Sounds good JSR, can't wait to see the results!!
Posted: Thu Jan 21, 2010 5:00 pm
by jackssmirkingrevenge
Here's what the action looks like so far, if it looks a bunch of scrap loosely held together by copious amounts of binary adhesive, it's because it is
Hope to have it ready for single shot testing by the end of the weekend.
