I'm just waiting now for all the ******** to turn up and say that "O rings are old hat and don't work"
LOL
I have several HW's with O ring conversions and they are amazing.
My 1966 HW55T is currently away having the same treatment.
Matty
Last edited by MattyBoy; 02-12-2013 at 09:30 PM.
Opportunity is missed by most people, because it is dressed in overalls and looks like work.
Matty, the bonus the Vortek conversion has is that is is essentially still a synthetic seal, so it gives the soft shot feel such seals give BUT if flies faster as an O ring is doing the sealing with less friction. So, you gain power and you gain the soft shot feel...so it usually is a win win using them.
Plus on the 55 the old seal is 11mm tall, the new seal you are using is 6mm tall, so you gain around 5mm stroke, which is enough to push the gun to 10fpe with out having to use a harsh spring. My 55 is so easy to cock it feels like it would never do 6fpe never mind 10.5fpe.
O rings are fine, as long as the transfer port is small enough to allow piston braking but large enough to allow good flow.
Opportunity is missed by most people, because it is dressed in overalls and looks like work.
BSA are famous for being tight yes - The grooves in the piston heads have to be made a little deeper - only a little though...
AA Sidelever O rings are not to tight , they slide nicely on the guns I have stripped and serviced
I expect you would have them even less crushed though
Matty
Opportunity is missed by most people, because it is dressed in overalls and looks like work.
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.
so they intentionally made some Jackals leaky and slammy to lower power?
what they should have done is built the nose of the piston out say 3mm to drop the swept volume a little, less air = less power..and fitted a slightly weaker spring.
Im sorry, i find this shocking that they made guns leaky to get the power down, no wonder they were horrid to shoot.
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
Opportunity is missed by most people, because it is dressed in overalls and looks like work.
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.