Quote Originally Posted by greenwayjames View Post
The predecessor of those was the Jackal. Made by Sussex Armoury using as a main subcontractor the company that later was AA. From a very reliable source who worked there on a top secret project (cant be discussed due to secrecy agreements on an open internet forum) I got some information on the use O rings in the Jackal. JB said that after blacking and before assembly the cylinders were lightly honed using something called a Flexi-hone. These were brought in from the US and looked like bottle brushes with abrasive balls in the bristles. This removed any blacking and left a crosshatched finish. When checked for velocity some .22" Jackals went over the top and a quick production line fix was to ream the loading tap slightly oversize to drop velocity a little.
I have 3 Jackal Branded guns and they are not as nice to shoot as the later AA Branded guns. Perhaps this is why they do not easily make power above 10 ft lb?

Why NSP thought it was OK to enlarge the tap hole thus allowing blow-by is beyond me!

I shall be measuring the loading apertures now - may have to go down the brass sleeving route to get any oversized ones back to 5.52/53 or whatever is correct.

Matty