SKC1 pneumatic copper sniper

[spudamine]

To connect the bolt I've drilled a hole through the barrel and threaded it. The bolt is placed into a piece of steel tube which acts as a spacer and screwed into the barrel. This only works on barrels with a thick enough wall to hold the thread, I used 1" aluminium with a 1/8"(3mm) wall. It wouldn't work with regular copper, not sure about PVC.
Using a thick walled barrel does carry weight and size penalties, but it does have some useful advantages, easy to put nice deep o-ring grooves into, stiff for accuracy and very strong, useful if you don't live in the US and want to put a silencer on
The semi I am planning at the moment will have an aluminium inner barrel with a copper outer barrel, sheathed in stainless for good measure