I know I promised to update this long long time ago but I had other things to do
the mechanism stays the same but I switched from a flow through bolt to a solid bolt... there is a pic of it created in sketchup in one of my posts here...
ammo is loaded on one side of the T and is pushed by the bolt through it to the other side...
there are two ports cut in the barrel with a dremel: one for ammo and the one through which air flows into the barrel (directly in the middle of the T above the barrel)
here a vid showing the gun and how it operates...plus, one of those 'oops!!' moments (I accidentally hit some thing I shouldn't)
there are virtually no flow restrictions at least I couldn't notice any difference between this and a single shot version of the same rifle (which was basically a muzzle loading single shot marble gun)
mag capacity is about 7 rounds in these vids but I can use even a 1 litre cola bottle as a hopper...
pressure used in the vids - roughly 150 psi
distance to the target - about 15 meters
notice the 'bamboo shot' (literally)
at :38... it nicely shattered a bamboo stick
thanks to charigun (an external ballistic program for airguns) I know that marbles lose roughly 50% of their muzzle energy at 30 - 35 meters... so I am thinking again about switching to a smaller caliber (0.965mm ball bearings) and switching to 88g co2 cartrides...
I see certain advantages to it apart form better external ballistics of ammo, mainly:
-lower air consumpion
-possbility of adding an inbuilt full barrel lenght coax silencer
with if you have other ideas as to which caliber I should choose feel free to post it
I run out of ammo today... more vids soon