Hi,
Well although the cartridges are the same dimensions and pretty much identical to a normal 12 Bore cartridge.
The Starter cartridge has carbon particles instead of lead shot in them, this propells the piston over.

Here is a rough guide to starting one (from memory, i dont own one, but have friends who do).

1)Open throttle fully.
2)You take a threaded holder out of cylinder head first and prime engine by turning over with handle.
3)You set the arrow on the fly wheel inline with the arrow on frame,
4)Then set decompressor mechanism by placing the litle wheel one turn over on grooves on flywheel.
5)Set valve on cylinder head to cartridge start position.
6)Remove cartridge holder and insert cartridge, Tightening with a gentle tap from hammer.
7)Then you roll up a small square of paper (This is soaked in saltpetre, i believe).
8)You insert paper into threaded Holder and light exposed end with lighter or match. Then you blow out flame on paper, so it just glows ( very tricky on a windy day)
9)Re insert paper holder, also tightening with hammer.
10)Stand and tap pin on head of cartridge holder, smartly with hammer.
After a bang she is normally away. fingers crossed.

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