Few people know that this was not originally produced as the usual type of Air Rifle.
The Webley MKII, was made to provide a form of cheap instructional training for service personnel, which was becoming vital at this time.
For this purposes Webley decided to use the explosive capabilities of the internal combustion engine.
Therefore the power tube was made from high quality steel and the piston has a bronze piston ring to cope with the conditions encountered therein.
Furthermore, Webley supplied a particular grade of oil to use for the correct degree of explosive energy required for pellet propulsion (commonly referred to as dieseling).
Sometimes, Dieseling occurs in other Air rifles, due to oil being present in the pressure cylinder but in this case, it was by design.
Dieseling is often experienced in Air weapons having Leather piston washers,
as they retain a certain amount of oil, but this can cause seal damage and inconsistent velocities.
However, Some Webley early pistols used a similar type of piston ring for the same reason as the MKII.
This explosive technique was later taken to higher levels by Weihrauch during the second World War,
when they made their Barakuda Rifle, that actually had a carburettor on it.
Another interesting fact: I understand that Weihrauch in German means “Holly Smoke”.
I think it originally refers to the smoke given off by candles in a church.
A Webley Service rifle, fired without any oil in the system produced very little power, however when a tiny amount of oil is present, they perform quite differently.
Whilst the Webley oil is no longer sold, I have found that lightly oiling with good old fashioned 3 in one cycle oil, works just fine, for quite a few shots before more is required.
Care must be taken not to overdo the amount of oil, as the performance may become sporadic, because only a very tiny amount of it is required.
Whilst the performance of the rifles I experimented with, did improve quite considerably, none of them ever approached the 12 ft/lb legal limit in my experience.
I did measure all of the velocities just to make sure.
However, I expect that if an exceptionally powerful spring was fitted then the limit would be exceeded, but that would not be beneficial for the rifle, or the person concerned.
I am really enjoying using my Webley MkII in the garden as it makes a change to shoot something with good quality open and peep sights that will consistently hit the target,
without having to bother with optics. I had really forgotten just how good these rifles were, and in most cases, still are, when used correctly.
Pheonix
The Pheonix is our updated version of something similar to the original rifle, but I have used technology, developed for our twin piston rifle,
to produce an efficient forward cocking, backward moving piston action, that will produce energy levels of close to the legal UK limit, without the necessity of dieseling.
Click on this link for more details Pheonix