I will check the piston weight a few days later.
@Shed tuner:"My guess is the power is fairly neutral, as you have sacrificed some combustion when moving away from leather."
Do you think it will have more power with a leather seal but 5mm less stroke ?How many percentage of the power is due to the combustion ?
I don't achieve to post some photos...I could show you my 35 nickel-plated with a nice home made walnut stock.
All that work for 8 fpe ... you can get that out of a HW30 without even trying in .22.
Just read this thread with some interest as I picked up a 35s a few years back in good order and threads like this you can often glean valuable information from on improving a model.
From my point of view reading this thread I would simply go the direction of a strip, degrease, swap over head for vortex replacement, size it carefully, fresh lube and re assemble. I think I would likely chrono gun prior to strip down and if power is healthy I would retain main spring. If not replace that same time.
Some very valid points made above however. Whereas the later Diana guns are easier to strip and reassemble, the three ball unit of the 35 would be a balls ache (no pun intended), should there be a need to repeat procedure a few times to adjust power and get things right. To me that's biggest hurdle. I've no doubt that unless you've got a gun with a major defect there shouldn't be too much drama getting above 10.5 and even quite close to 12 with a 35. Again as has been pointed out a caveat to this would be that would be in .22 calibre. I suspect a good .177 would top out around 10-10.5. Probably healthy enough for closer range small vermin.
Again as has been pointed out previously it might be a whole lot better to look towards improvement on smoothness of the gun for a given power rather than a sole aim for ultimate power as there are other models in the Diana range that you can achieve that objective easier with. I've used synthetic seals on numerous guns and almost all have resulted in improvements in power. But ultimately for me at least I would prefer to shoot a 10.5 ft llb 35 that was silky smooth to operate and as quiet as can be than a 10.5 gun that is akin to a bucket of spanners.
And ultimately a 10.5 gun may be sweeter and more accurate than a 11.7 gun anyhow.
Dave
The 35S was the fancy version of the 35, not a more powerful one. It's not like cars where putting an 'S' on the boot gives 100 extra horses.
The Super Meteor and the Meteor are the same mechanicals in the old BSA range but the Super had a Monte Carlo cheek-piece, a deeper fore-end and a thick ventilated recoil pad. It's the stock that made it 'super', same with the Original Diana.. nice stock and sights.
The mysterious Diana 35B is the one that is supposed to be powerful but I cannot see how.
I think it was Gedfinn on here who claimed it, also it is mentioned in the Wesley book from the 60s ... I'll have to track it down but probably a matter of a strong spring and the lack of a chronograph.. Relum Tornados were thought to be powerhouses back then as well, but they make about 8 fpe. Impressions can be deceptive.
The 35s in the Middle East might be Indian copies? The 35 was a highly cloned design.
I have actually got an old tired .22 35 myself, so I should have a go as well at supertuning the freak!
As I see it the problem lies mainley in the transfer port construction/dimensions from the factory.
Even if the port diameter is sized down the length remains the same and "strungles" (if I may use this word) the power of the compressed air.
A skilled gunsmith with the appropriate tools could re-shape the transfer port dimensions into something much more efficient i.e. from 26x4 mm to 10x3 mm. This would involve the modification of the barrel to the block (removal of the barrel and re-fitting in a new position protruding from the block rear end) and the making of a new barrel seal groove.
It is a lot of trouble to make but it can be done.
In this way the rifle will mimic the performance of a new air rifle of similar internal parts (and dimensions between them) but in a vintage look.
Forgive me for the long message.
sleaving the port down to 3mm makes sense
shortening the port is impossible without basically makikng a new cylinder, unless you do a vulcan type barrel that seats back into the breach face.
Always looking for any cheap, interesting, knackered "project" guns. Thanks, JB.
I am not familiar with the Vulcan air rifle barrel construction but I checked it now (with google) and it is very close to the project.
Here are a couple of pictures of the Gamo Hunter 1250 rifle from another site that shows the final outcome of such a piece of engineering.
https://downloader.disk.yandex.ru/pr...&size=1903x892
http://24ars.ru/upload/iblock/1da/1d...7fe811dbd5.jpg
IIRC the 35S does use a different piston, spring, or both. Though that may be to accommodate the articulated cocking link and ABT rather than to increase power.
The 35 is a nice rifle. I have two. I think this thread shows that trying to add 1ft-lb to their muzzle energy would require significant engineering. And why do it when you could just buy, say, a Diana 34 or one of many other rifles of similar size and weight but slightly higher power?