The $100 challenge.....

Has anyone been able to shoot some half-decent groups at 10m??  I got my gun back together tonight and it's silky smooth so I'm really happy about that, but I'm still struggling to get any semblance of a decent group.  Thinking about it as I'm typing - perhaps it is the red dot (Hawke)?  I did some sighting in at 6m and got a very tight group initially, but it just went haywire when I went back to 10m.  Different pellets are going in completely different directions with a wide scatter.  The mount is rock solid, so I'm off the sports shop in the morning to see if he has a Nikko Sterling in stock.  

There's a very noticeable misalignment between the barrel and cylinder centrelines so there's not much point in fitting the Tasco until when & if I get around to truing that up.  The bore looks nice and straight and the rifling also looks good.  I must be getting a bit of grease coming through though as I can smell it.  Perhaps it's dieseling and causing this issue?

Well, no shooting tonight either.  I thought I had everything ready for reassembly, but I still couldn't get the cocking shoe located through the slot and inside the piston where it should be.  I did some measurements and figured that I'd managed to shrink the centre swage on the piston even more when clamping it in the lathe leaving too little clearance between the inner wall and the spring.  The next move was to thin down the shoe, but that still wasn't enough.  I managed to find an old piece of pipe of a suitable size, cut and machined it to suit then pressed it inside the piston to gain some clearance.  This worked OK, but of course opened the slot up more allowing one leg of the shoe to be free to disengage if it so chooses.  Out came the files and a slot created on the leading edge so when the cocking pressure comes on it should be firmly locked in place.  Test fitted before I packed up and looking good for tomorrow night.

I really hate the piston design, construction and the material they've used.  The only good thing about it is the centre rod which appears to be hard as hell.  The tube itself though is very soft (tapping the slot edges true with a copper head hammer after I'd spread it left visible impressions in the 'steel'), the extent of the swaging is far more than necessary and the cocking arm slot is too wide.  It's a shame because the cylinder is really quite nicely made.  I'll persist with this part for the time being so I can at least fire a few more shots, but I may yet resort to making my own from a piece of pipe and utilising the original centre rod and base.