Vortek Weihrauch 'O' Ring Piston Head Conversion

[MattyBoy]

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

[greenwayjames]

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

JB said it was Sussex Armoury produced the rifles. Most of the components being made on the local trading estate. He said quick fixes have to be carried out otherwise production is expensive. Like most .22" taploaders maximum power and soft shooting was only achieved using the contemporary Eley Wasp. Just the same as an Airsporter I used to have. BSA sold a little kit to expand the skirts of Wasps to get maximum power out of their S models. It made an enormous difference to the shooting characteristics.

[MattyBoy]

JB said it was Sussex Armoury produced the rifles. Most of the components being made on the local trading estate. He said quick fixes have to be carried out otherwise production is expensive. Like most .22" taploaders maximum power and soft shooting was only achieved using the contemporary Eley Wasp. Just the same as an Airsporter I used to have. BSA sold a little kit to expand the skirts of Wasps to get maximum power out of their S models. It made an enormous difference to the shooting characteristics.

Interesting stuff

Now then...

I have a Jackal branded action from I guess the early 80s which I bought as a doer upper. I've never shot it - the piston is cracked on the nose...

anyway...

I have this lunch time measured the diameter of the exit hole in this gun's tap...

The exit hole is <5.3mm

This is the opposite to that which I expected!

This must result in a pellet too small for the 5.50 barrel for sure?

Really surprised to find this result!

Matty