Originally Posted by
Scubashot
I had one in my HW77 for over 25 years as part of a Maximiser tuning kit which included replacement plastic/delrin spring guides, a steel piston sleeve and a selection of lubricants.
I never had any problems with it until a couple of years ago when I finally chronoed the gun and found it running over 13 ft-lbs.
I stripped the gun and found no evidence of damage to either the spring or rifle but thought it was maybe time to fit a new high tech modern kit, especially as the Ox gets such bad press.
I ordered and fitted a full drop in V- Mach kit of spring, piston sleeve, top hat and guides, piston seal etc. This was supplied specifically for my 0.22" rifle with 25mm piston but still required extensive fettling to keep it within the 12 ft-lbs limit. After the seal bedded in the power kept climbing and I kept removing preloaded washers until there were no more to remove. I then collapsed a coil of the spring. I have since had a failure of the spring guide which was not even fitted to the modified end of the spring.
I refitted the spring guide originally supplied with the Maximiser kit and fitted a single preload washer and finally have a stable and acceptable power output with an accurate rifle that shoots better than me.
In fairness, Steve Pope of V Mach has a good and I am sure well deserved reputation but has been unavailable for some time owing to illness. He would no doubt have been willing to help with my problems had he been around.
Coming back to the original post finally: if I was in a similar position again I would probably just reduce the Ox spring rather that spend a chunk of change and still have to tailor a kit to my specific rifle.
In my limited experience the Ox has not been as bad as it is usually portrayed : maybe it has more to do with some 1980s power hungry owners choosing that spring before packing it with preload and wrecking rifles.