Ox springs

[bozzer]

I think it was a combination of what Rich said about square section when it's wound into a coil ( it isn't truly square any more and some of the 'corners' point into guides etc ), and the posters who have mentioned correctly fitting guides.

I've opened up a few abused HW77/97 that were still using the old splayed ended ill fitting Weihrauch
rear guide. People had fitted an Ox spring in the search for mega power and the length of the spring and the poor fitting between the rear, soft metal guide and the inside of the Ox had meant that the corners of the square section had made a real mess of the guide.

People also put these in some of the earlier Webleys. Rifles designed for probably 9 or 10fp and then maybe the Vulcan could squeeze 12fp. Again way over sprung with Ox springs crammed in there and poor fitting. Results would be that the inside of the piston would be mauled and the very harsh firing cycle meant that the weakly designed main cylinder's holes would elongate ( where the hardened end block holding pin went through ).

I did come across an old 97 that had a square section spring. I have no idea if it was an Ox or one of the ones that HW fitted in the 97's for a while. It looked different than the Ox and Air Force springs. Even when coiled the coils were more square than the Ox. So the guides and inside of piston pretty much ran along the flats of the spring and not on turned over corners like on the Ox's I'd seen. When I Put some decent fitting guides in that spring and fitted it to a 97 it shot very well indeed.

[Zomboid]

I fitted an Ox to my old BSA 635 and my Dad's Mercury - along with a couple of other bits and pieces. The results were fine. Shot cycle was fine too.

However when I came to giving the 635 its first service in 15 years (having been stored in a cellar for that long) I noticed there were notches in the spring. Meaning that there were bits of metal in the cylinder. This I would say goes with the previous post about the edges on the square section.

Yes I managed to get a decent performance. No I wouldnt recommend them. My 635 now has a reduced length old Titan (not XS) spring in it and shoots incredibly sedately.