I've not done anything on this weapon for a long while as the brick wall i've faced is the strange shape at the front of the wooden stock that joins that to the tube that runs below the barrel.
It looks to be some kind of fork for a wheel or gear or something but, try as i might, i've not been able to find anything suitable.
Fed up with waiting, and really wanting to crack on, i've gone and made my own from Plasticard.
Before that though, i added a wooden pole to the front of the stock to take the weight of the barrel that'll be going on later.
With that pole and my new shape built, i could then cover up the pole with a plastic tube (a cut down section of the reusable rockets from the Airfix Space Shuttle kit) and attached a cog at the very front.
Again, i've not been able to find a match for that and this one is much bigger than it should be. But, its in keeping with the original and helps balance the back-heavy assembly so far of having a solid wood section at the rear.