That Original 66

[Phil Russell]

Does this rate as a Collectable? I tend to think so. While I have serviced several pistols with the twin pistons, this 66 was my first rifle. Initial fps was about 170 and terribly noisy. Service went quite well if you ignore the senior moment when I got the pistons in upside down and did not notice until I had rebuilt the rifle ... such is old age and life; and whoever designed that hideous long spring set needs shooting. If there is an aftermarket single spring, tell me.
But one thing puzzled me and someone on here may know the answer. The 'compensation' or 'slave' piston has a screwdriver slot in the end and the spring guide / piston head receiver can be removed by turning the slot 90 degrees to release the said guide assembly from the main body. At first I thought it was a short cut to fitting the new seal but with the seal fitted I could not get the guide assembly to fit onto the body. Then, with the seal off again and the guide assembly back on the body it was more awkward than normal to fit the seal because of some play in the guide which allowed the head to move back into the body a tad, reduced the space available for the seal to slip over ... I hope you are following this. The solution was to use a large drift, longer than the piston body, inside the guide to hold the head proud when fitting the seal.
But why make this piston like that? I guess there was a reason and I would love to know.
Does anyone know?
After a good service the 66 is now at c. 610 fps so I deem it a job well done.
Cheers, Phil

PS. Thank you to Neil Price for his excellent guide(s) in Airgunner from a couple of years ago.

[Geezer]

Can't help you on the mechanicals (I keep not finding time - I.e. not quite having the courage - to open mine up and get it working again).

But definitely collectable. And, when working well, a really impressive bit of kit that would probably cost well over a grand if made now to the same standard.

Used to spend hours back in the day using mine to shoot match heads or the petals off daisies.

[Benelli B76]

Strange that the balance piston seals never seem to deteriorate but the compression seals crumble up. The only thing I can think it is from liquid (oil) added through the transfer port. The bacteria that destroy the polyurethane love moisture.

Baz

[Hsing-ee]

Dunno but I nearly bought a cheap one to put in a normal sporter stock and thus create the ultimate back-yard break-barrel plinker ...

[Drew451]

I find the 66 in standard form very manageable for a match rifle.

[PhatMan]

Phil,

IIRC, it was designed like this to allow a less slow way of replacing the mainsprings

The slave piston head came off, then the springs could be replaced without any further dismantling.

If only Diana had designed the rifle like the FWBs & Anschutz 250, whereby the 'complicated bits' can be removed as a single unit by undoing two (2) screws !!

Having fixed spot welded cages, and the need to remove zillions of pins and bits & peices, and the jigsaw of replacement definitely stops people like me from even thinking about stripping them

The 66, IMHO, is definitely a collectable, and a superb shooting rifle.

I really, really like mine - it groups better than my FWB300's (300 & 300 SU), and indeed better than my Diana 75

A very fine rifle

Have fun & a good weekend

Best regards

Russ